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Journal of the Korea Concrete Institute

J Korea Inst. Struct. Maint. Insp.
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  • Korea Citation Index (KCI)

  1. ํ•™์ƒํšŒ์›,๊ณ ๋ ค๋Œ€ํ•™๊ต ๊ฑด์ถ•์‚ฌํšŒํ™˜๊ฒฝ๊ณตํ•™๋ถ€ ํ•™์„์‚ฌ์—ฐ๊ณ„๊ณผ์ •
  2. ์ •ํšŒ์›,๊ณ ๋ ค๋Œ€ํ•™๊ต ๊ฑด์ถ•์‚ฌํšŒํ™˜๊ฒฝ๊ณตํ•™๊ณผ ๋ฐ•์‚ฌ๊ณผ์ •
  3. ์ •ํšŒ์›,๊ณ ๋ ค๋Œ€ํ•™๊ต ๊ฑด์ถ•์‚ฌํšŒํ™˜๊ฒฝ๊ณตํ•™๊ณผ ์„์‚ฌํ›„์—ฐ๊ตฌ์›
  4. ์ •ํšŒ์›,XFINASIT General Manager
  5. ์ •ํšŒ์›,๊ณ ๋ ค๋Œ€ํ•™๊ต ๊ฑด์ถ•์‚ฌํšŒํ™˜๊ฒฝ๊ณตํ•™๋ถ€ ๊ต์ˆ˜, ๊ต์‹ ์ €์ž



ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ๋ฌผ, ์œ ํ•œ ์š”์†Œ ํ•ด์„ ํ”„๋กœ๊ทธ๋žจ
Substructure for offshore wind energy, FEA program

1. ์„œ ๋ก 

์ตœ๊ทผ ํƒ„์†Œ ๋ฐฐ์ถœ ๊ฐ์†Œ๋ฅผ ์œ„ํ•œ ๋…ธ๋ ฅ์˜ ์ผํ™˜์œผ๋กœ ์ง€์† ๊ฐ€๋Šฅํ•œ ์—๋„ˆ์ง€์— ๊ด€ํ•œ ๊ด€์‹ฌ์ด ๊ฐ€ํŒŒ๋ฅด๊ฒŒ ์ฆ๊ฐ€ํ•˜๋ฉด์„œ ์‹ ์žฌ์ƒ์—๋„ˆ์ง€์— ๋Œ€ํ•œ ์ˆ˜์š”๋„ ํญ์ฆํ•˜๊ณ  ์žˆ๋‹ค(Yi et al., 2019). ํŠนํžˆ, 2015๋…„ 12์›” 12์ผ โ€œ์ง€๊ตฌ ๊ธฐ์˜จ์˜ ์ƒ์Šน ํญ์„ 2โ„ƒ๋ณด๋‹ค ํ›จ์”ฌ ๋‚ฎ๊ฒŒ ์œ ์ง€ํ•˜๊ณ  1.5โ„ƒ ์ดํ•˜๋กœ ์ œํ•œํ•˜๊ธฐ ์œ„ํ•œ ๋…ธ๋ ฅํ•œ๋‹คโ€๋Š” ํŒŒ๋ฆฌํ˜‘์•ฝ์ด ์ฒด๊ฒฐ๋จ์— ๋”ฐ๋ผ ๊ตญ๋‚ด์—์„œ๋„ 2030๋…„๊นŒ์ง€ ์˜จ์‹ค๊ฐ€์Šค ๊ฐ์ถ•๋ชฉํ‘œ๋ฅผ 37%๊นŒ์ง€ ๊ฐ์ถ•ํ•œ๋‹ค๋Š” ๊ณ„ํš์„ ๋ฐœํ‘œํ•˜์˜€๋‹ค(Ministry of Environment, 2018). ์ด์— ๋งž์ถฐ ์ตœ๊ทผ ์šฐ๋ฆฌ๋‚˜๋ผ๋„ ์‹ ์žฌ์ƒ์—๋„ˆ์ง€ ๋น„์ค‘์„ 2021๋…„ ๊ธฐ์ค€ 6.3%์—์„œ 2030๋…„๊นŒ์ง€ 20%๋กœ ํ™•๋Œ€ํ•˜๋Š” ๋ฐฉํ–ฅ์œผ๋กœ ์—๋„ˆ์ง€์ •์ฑ…์„ ๊ฐœ์ •ํ•˜์˜€๋‹ค(Ministry of Trade, Industry and Energy, 2022). ์›๋ณ„ ๋น„์ค‘์„ ๋ณด๋ฉด 2021๋…„ ๊ธฐ์ค€ ํƒœ์–‘๊ด‘์ด 38.0%, ๋ฐ”์ด์˜ค๊ฐ€ 30.5%, ํ’๋ ฅ์ด 4.8%์ด์ง€๋งŒ 2030๋…„๊นŒ์ง€ ํƒœ์–‘๊ด‘ 57%, ํ’๋ ฅ 28%, ๋ฐ”์ด์˜ค 5%๋กœ ํ’๋ ฅ์˜ ๋น„์ค‘์„ ๋Œ€ํญ ํ™•๋Œ€ํ•  ๊ณ„ํš์ด๋‹ค(Ministry of Trade, Industry and Energy, 2022).

ํ’๋ ฅ๋ฐœ์ „์€ ๊ฐœ๋ฐœ ์‹œ ํƒ€ ์‹ ์žฌ์ƒ์—๋„ˆ์ง€์›์— ๋น„ํ•ด ๋†’์€ ์šฉ๋Ÿ‰์˜ ์—๋„ˆ์ง€๋ฅผ ์–ป์„ ์ˆ˜ ์žˆ๊ธฐ ๋•Œ๋ฌธ์—, ์œก์ƒ ๋ฟ ๋งŒ ์•„๋‹ˆ๋ผ ๊ณ ํ’ˆ์งˆ์˜ ํ’ํ™ฉ์ž์›์ด ํ™•๋ณด๋  ์ˆ˜ ์žˆ๋Š” ํ•ด์ƒํ’๋ ฅ ๋ฐœ์ „๋‹จ์ง€๊ฐ€ ๊ฐœ๋ฐœ๋˜๊ณ  ์žˆ๋‹ค(Lee et al., 2012). ์„ธ๊ณ„ํ’๋ ฅ์—๋„ˆ์ง€๊ฐœ๋ฐœํ˜‘ํšŒ(GWEC)์˜ 2022๋…„ ๋ณด๊ณ ์„œ์— ๋”ฐ๋ฅด๋ฉด, ํ•ด์ƒํ’๋ ฅ๋ฐœ์ „๋‹จ์ง€ ์‹ ๊ทœ ์„ค์น˜ ์šฉ๋Ÿ‰์€ 2022๋…„ ๊ธฐ์ค€ 8.7GW์ด๋ฉฐ 2026๋…„์—๋Š” 31.4GW๋กœ 3.6๋ฐฐ๊ฐ€๋Ÿ‰ ์ฆ๊ฐ€ํ•  ๊ฒƒ์œผ๋กœ ๋ณด๊ณ  ์žˆ์œผ๋ฉฐ ์ด๋Š” ์‹ ๊ทœ ์„ค์น˜ ์ด๋Ÿ‰์˜ 25%์— ํ•ด๋‹นํ•˜๋Š” ๋น„์œจ์ด๋‹ค(Ministry of Trade, Industry and Energy, 2022).

ํ•ด์ƒ์— ์„ค์น˜๋˜๋Š” ๊ตฌ์กฐ๋ฌผ์€ ์กฐ๋ฅ˜์™€ ํŒŒ๋ž‘ ํ•˜์ค‘๊ณผ ๊ฐ™์€ ๋™์ ์ธ ํ•˜์ค‘์— ์ƒ์‹œ์ ์œผ๋กœ ๋…ธ์ถœ๋˜๋ฉฐ, ํ’ํ•˜์ค‘๊ณผ ๋ฐœ์ „๊ธฐ ์šด์šฉ์ด ๋ณตํ•ฉ๋˜์–ด ๋ฐœ์ƒ๋˜๋Š” ์ง„๋™ ํŠน์„ฑ๊นŒ์ง€๋„ ์„ค๊ณ„์— ๊ณ ๋ คํ•  ํ•„์š”๊ฐ€ ์žˆ๋‹ค(Jonkman, 2009). ์ด๋Š” ์ •์ ์ธ ํ•˜์ค‘ ์ƒํƒœ๊ฐ€ ์ง€๋ฐฐ์ ์ธ ์œก์ƒ๊ตฌ์กฐ๋ฌผ์˜ ํ•ด์„๊ณผ๋Š” ๋Œ€๋ณ„๋˜๋Š” ํŠน์ง•์œผ๋กœ์„œ, ํ•ด์ƒํ’๋ ฅ ๊ตฌ์กฐ๋ฌผ์˜ ํ•ด์„์—๋Š” ์ด๋“ค์˜ ํšจ๊ณผ๋ฅผ ์ƒํ˜ธ ์กฐํ•ฉํ•˜์—ฌ ๊ณ ๋ คํ•  ํ•„์š”๊ฐ€ ์žˆ๋‹ค. ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ๋Š” ๋ธ”๋ ˆ์ด๋“œ์™€ ๋ฐœ์ „๊ธฐ๋ฅผ ๋ฐ›์น˜๊ณ  ์žˆ๋Š” ๊ธฐ๋‘ฅ ๋ถ€ ์•„๋ž˜๋กœ ์ •์˜ํ•˜๋ฉฐ ์ด๋ฅผ ํ•ด์„ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” (1) ๋ธ”๋ ˆ์ด๋“œ ๋ฐ ํ„ฐ๋นˆ์˜ ๊ณต๋ ฅ ๊ฑฐ๋™, (2) ์ง€์ง€๊ตฌ์กฐ์™€ ํƒ€์›Œ์˜ ๊ตฌ์กฐ ๋™์—ญํ•™ ๊ฑฐ๋™, (3) ํ•ด์–‘ ์™ธ๋ ฅ๊ณผ ์ง€์ง€๊ตฌ์กฐ์™€์˜ ๋™์  ์ƒํ˜ธ์ž‘์šฉ, (4) ๊ณ„๋ฅ˜๋ผ์ธ์˜ ๋™์  ๊ฑฐ๋™์„ ๋™์‹œ์— ๊ณ ๋ คํ•ด์•ผ ํ•œ๋‹ค(Oh et al., 2019).

๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๊ตญ๋‚ด ๊ฑด์„ค์‹œ์žฅ์—์„œ ์ƒˆ๋กญ๊ฒŒ ๋Œ€๋‘๋˜๊ณ  ์žˆ์ง€๋งŒ ๋‹ค์†Œ ์ƒ์†Œํ•œ ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ๋ฌผ์˜ ํŠน์ง•๊ณผ ํ•ด์„์— ํ™œ์šฉ๋  ์ˆ˜ ์žˆ๋Š” ๊ตญ๋‚ด์™ธ ํ•ด์„ํ”„๋กœ๊ทธ๋žจ์˜ ์žฅ๋‹จ์ ์„ ๊ฒ€ํ† ํ•˜์˜€์œผ๋ฉฐ, ๋‹จ์ผ ํ”Œ๋žซํผ์—์„œ ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ ํ•ด์„์„ ์ˆ˜ํ–‰ํ•  ์ˆ˜ ์žˆ๋Š” ํ•ด์„ ํ”„๋กœ๊ทธ๋žจ์˜ ๊ตฌ์„ฑ์— ๋Œ€ํ•ด ์ œ์•ˆํ•˜์˜€๋‹ค. ํ”„๋กœ๊ทธ๋žจ์˜ ์ ์šฉ์„ฑ์„ ๊ฒ€์ฆํ•˜๊ธฐ ์œ„ํ•ด ๊ตญ๋‚ด ์„œ๋‚จํ•ด ์ง€์—ญ์˜ ๋ฐ์ดํ„ฐ๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ ํƒ€ ํ•ด์„ ํ”„๋กœ๊ทธ๋žจ OpenFAST์˜ ๊ฒฐ๊ณผ์™€ ๋น„๊ตํ•˜์˜€๋‹ค.

2. ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ ๊ฑฐ๋™์˜ ๋‹ค์ค‘๋ฌผ๋ฆฌ ํŠน์„ฑ

2.1 ์ง€์ง€๋ฐฉ์‹์— ๋”ฐ๋ฅธ ์ง€์ง€๊ตฌ์กฐ ํŠน์„ฑ

Fig. 1์€ ์ˆ˜์‹ฌ์— ๋”ฐ๋ผ ๋‹ค์–‘ํ•œ ํ˜•ํƒœ์˜ ์ง€์ง€ ํŠน์„ฑ์œผ๋กœ ๊ตฌ์„ฑ๋˜๋Š” ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ์ด๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ 50m ๋ฏธ๋งŒ์˜ ์ €์ˆ˜์‹ฌ์—์„œ๋Š” ์ง€์ง€๊ตฌ์กฐ๋ฌผ ํ•˜๋ถ€๊ฐ€ ํ•ด์ € ์ง€๋ฐ˜์— ๊ณ ์ •๋˜๋Š” ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ(Fixed substructures)๋ฅผ ์‚ฌ์šฉํ•˜๊ณ , 60m๋ฅผ ์ดˆ๊ณผํ•˜๋Š” ์ˆ˜์‹ฌ์—์„œ๋Š” ๊ณ ์ •์‹ ๋Œ€์‹  ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ(Floating substructures)๋ฅผ ์‚ฌ์šฉํ•œ๋‹ค(Kim, 2019). ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ์˜ ์ง€์ง€๋ ฅ์€ ๋ถ€๋ ฅ์œผ๋กœ ํ™•๋ณดํ•˜๊ณ  ํ‰๋ฉด ์ƒ์˜ ์œ„์น˜๋Š” ์•ต์ปค์™€ ๊ณ„๋ฅ˜๋ผ์ธ์„ ์ด์šฉํ•ด์„œ ํ™•๋ณดํ•œ๋‹ค. ๊ตฌ์กฐ๋ฌผ ์ „์ฒด์˜ ๊ธฐ์šธ๊ธฐ์— ๋Œ€ํ•œ ์ €ํ•ญ๋„ ๋ถ€๋ ฅ์˜ ์ฐจ์ด๋กœ ์ง€์ง€๋œ๋‹ค.

ํ„ฐ๋นˆ, ๋ธ”๋ ˆ์ด๋“œ ๋ฐ ํƒ€์›Œ๋Š” ๊ณ ์ •์‹๊ณผ ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ ๋ชจ๋‘ ๊ณตํ†ต์ ์ธ ์‚ฌํ•ญ์ด๋‹ค. ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋Š” ํ•ด์ € ์ง€๋ฐ˜์„ ๊ด€ํ†ตํ•˜๋Š” ๊ธฐ์ดˆ๊ฐ€ ์ง€์ง€๊ตฌ์กฐ์˜ ์›€์ง์ž„์„ ์ง€์ง€ํ•˜๋ฏ€๋กœ ์ง€์ง€๊ตฌ์กฐ์˜ ์›€์ง์ž„์ด ์ƒ๋Œ€์ ์œผ๋กœ ์ž‘์•„์„œ, ํ•ด์–‘ ํ™˜๊ฒฝ ํ•˜์ค‘์„ ์‚ฐ์ •ํ•  ๋•Œ ํ•ด์–‘๊ณผ ์ง€์ง€๊ตฌ์กฐ์˜ ์ƒํ˜ธ์ž‘์šฉ์„ ์ตœ์†Œํ•œ์œผ๋กœ ๊ณ ๋ คํ•œ ๋ชจ๋ฆฌ์Šจ ๋ฐฉ์ •์‹์œผ๋กœ ๊ณ„์‚ฐํ•˜๋Š” ๊ฒƒ์ด ์ผ๋ฐ˜์ ์ด๋‹ค. ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ๋Š” ์กฐ๋ฅ˜์™€ ํŒŒ๋ž‘์˜ ์ž‘์šฉ์— ์˜ํ•ด ๋ณ€ํ˜•๋ฅ ์€ ์ž‘๋”๋ผ๋„ ์ƒ๋Œ€์ ์œผ๋กœ ํฐ ๋ณ€์œ„๊ฐ€ ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค. ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ์˜ ๋ณ€์œ„๋ฅผ ํ•ด์„ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์œ ์ฒด-๊ตฌ์กฐ์ฒด ์ƒํ˜ธ์ž‘์šฉ์„ ์ง์ ‘ ๊ณ ๋ คํ•˜๋Š” ๊ฒƒ์ด ํ•„์š”ํ•˜๋‹ค.

Fig. 1 Offshore wind energy substructures based on water depth level (Jung et al., 2021)
../../Resources/ksm/jksmi.2023.27.4.33/fig1.png

2.2 ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ

2.2.1 ๋ธ”๋ ˆ์ด๋“œ ๋ฐ ํ„ฐ๋นˆ์˜ ๊ณต๋ ฅ ๊ฑฐ๋™

๋ฐ”๋žŒ์˜ ์ž‘์šฉ์— ๋”ฐ๋ผ ๋ธ”๋ ˆ์ด๋“œ์— ๊ฐ€ํ•ด์ง€๋Š” ์™ธ๋ ฅ์€ ํ„ฐ๋นˆ์— ์šฐ๋ ฅ์œผ๋กœ ์ „๋‹ฌ๋œ๋‹ค. ๊ณต๊ธฐ์™€ ๋ธ”๋ ˆ์ด๋“œ์˜ ์ƒํ˜ธ์ž‘์šฉ์˜ ํ•ด์„์€ ๊ณต๊ธฐ ์œ ๋™์žฅ์„ ๋™์ ์œผ๋กœ ํ•ด์„ํ•ด์•ผ ํ•˜๋Š” ๋ฌธ์ œ๋กœ์„œ ๊ทนํžˆ ๋ณต์žกํ•˜๋ฏ€๋กœ, ํ’๋ ฅ๋ฐœ์ „๊ธฐ ํ•ด์„์šฉ์œผ๋กœ ์ด๋ฅผ ๊ฐ„๋‹จํžˆ ๊ทผ์‚ฌํ™”ํ•œ BEMT (Blade element momentum theory)๋ฅผ ์‚ฌ์šฉํ•˜๋Š” ๊ฒƒ์ด ์ผ๋ฐ˜์ ์ด๋‹ค. ๊ณต๊ธฐ ๋ฐ€๋„, ๊ณต๊ธฐ ์ ์„ฑ, ์Œ์†, ๋Œ€๊ธฐ์••, ์ˆ˜์ฆ๊ธฐ ์••๋ ฅ, ์™€๋ฅ˜ ํŠน์„ฑ๊ณผ ๋กœํ„ฐ-๋ธ”๋ ˆ์ด๋“œ์˜ ๊ธฐ๊ณ„์  ํŠน์„ฑ์น˜๊ฐ€ ํ•„์š” ๋ณ€์ˆ˜๋กœ ๊ณ ๋ ค๋œ๋‹ค(Naess and Moan, 2019). ๊ด€ํ–‰์ƒ ๋ธ”๋ ˆ์ด๋“œ, ํ„ฐ๋นˆ ๋ฐ ํƒ€์›Œ๋ฅผ ํ•œ ์„ธํŠธ๋กœ ๋ชจ๋ธํ•˜๊ณ  ์ด๋ฅผ ํ•ด์„ํ•œ๋‹ค. BEMT ๋ชจ๋ธ์—์„œ๋Š” ํƒ€์›Œ ํ•˜๋‹จ์„ ๊ณ ์ •ํ•˜๊ณ , ๊ณต๊ธฐ์˜ ์œ ๋™์— ๋”ฐ๋ฅธ ํ•˜๋‹จ์˜ 6 ์ž์œ ๋„์˜ ํƒ€์›Œ ํ•˜๋‹จ ๋ฐ˜๋ ฅ์ธ $F_{t}$๋ฅผ ๊ณ„์‚ฐํ•œ๋‹ค.

๊ณ ์ •์‹๊ณผ ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ ๋ชจ๋‘ ํƒ€์›Œ๊ฐ€ ์—ฐ๊ฒฐ๋˜๋Š” ์ง€์ง€๊ตฌ์กฐ ์ƒ๋‹จ์—๋Š” ์‹œ๊ฐ„ ์˜์กด์ ์ธ ๋ณ€์œ„๊ฐ€ ๋ฐœ์ƒํ•˜๋ฏ€๋กœ, BEMT ๋ชจ๋ธ์„ ์ˆ˜์ •ํ•˜์—ฌ ํƒ€์›Œ ํ•˜๋‹จ์— ๋ณ€์œ„์™€ ์†๋„๋ฅผ ๊ณ ๋ คํ•  ์ˆ˜ ์žˆ๋„๋ก ํ•ด์•ผ ํ•œ๋‹ค. ๊ฒฐ๊ตญ ํƒ€์›Œ ํ•˜๋‹จ ๋ฐ˜๋ ฅ์ธ $F_{t}$๋Š” ๋ณ€์œ„์˜ ํ•จ์ˆ˜์ด๋ฉฐ, $F_{t}=F_{t}(u,\: \dot{u})$๋กœ ์ˆ˜์ •๋œ๋‹ค.

2.2.2 ์ง€์ง€๊ตฌ์กฐ์˜ ๊ตฌ์กฐ ๋™์—ญํ•™ ๊ฑฐ๋™

์„ ํ˜• ๋™์ ์ธ ๊ตฌ์กฐ ์‹œ์Šคํ…œ์˜ ์šด๋™์€ ๋‹ค์Œ๊ณผ ๊ฐ™์ด ์ž˜ ์•Œ๋ ค์ง„ 2์ฐจ ์ƒ๋ฏธ๋ถ„๋ฐฉ์ •์‹์œผ๋กœ ํ‘œํ˜„๋œ๋‹ค.

(1)
$M\ddot{u}+ C\dot{u}+ K u = F$

์—ฌ๊ธฐ์„œ, $M$์€ ์งˆ๋Ÿ‰, $C$๋Š” ๊ฐ์‡ ๊ณ„์ˆ˜ (Damping coefficient), $K$๋Š” ๊ฐ•์„ฑ, $u$๋Š” ๋ณ€์œ„, $\dot{u}$๋Š” ์†๋„, $\ddot{u}$๋Š” ๊ฐ€์†๋„, $F$๋Š” ์ž‘์šฉ ์™ธ๋ ฅ์ด๋‹ค. ์œ„ ์ง€๋ฐฐ ๋ฐฉ์ •์‹์€ ๋‹จ ์ž์œ ๋„ ์‹œ์Šคํ…œ์— ๊ด€ํ•œ ์‹์ด์ง€๋งŒ, ๋‹ค์ค‘ ์ž์œ ๋„ ๋ฌธ์ œ์ธ ๊ฒฝ์šฐ์—๋„ ์‹ (1)๊ณผ ๊ฐ™์€ ํ‘œ์ค€ ํ˜•์‹์œผ๋กœ ๊ท€๊ฒฐ๋œ๋‹ค. ์‹ (1)์˜ ์งˆ๋Ÿ‰, ๊ฐ•์„ฑ๊ณผ ๊ฐ์‡„๊ณ„์ˆ˜๋Š” ๋งคํŠธ๋ฆญ์Šค ํ˜•ํƒœ๋กœ ์ „ํ™˜๋˜๊ณ , ๋ณ€์œ„, ์†๋„, ๊ฐ€์†๋„ ๋ฐ ์™ธ๋ ฅ์€ ๊ฐ ์ž์œ ๋„์— ํ•ด๋‹นํ•˜๋Š” ๋ฒกํ„ฐ ํ˜•ํƒœ๋กœ ๊ตฌํ˜„๋œ๋‹ค.

์ž‘์šฉ ์™ธ๋ ฅ์œผ๋กœ์„œ ํƒ€์›Œ ํ•˜๋‹จ์˜ ๋ฐ˜๋ ฅ, ํ•ด์–‘ ์™ธ๋ ฅ์— ์˜ํ•œ ํ•˜์ค‘์„ ์ค‘์ฒฉํ•ด์•ผ ํ•˜๋ฉฐ, ๋ถ€์œ ์‹์˜ ๊ฒฝ์šฐ์—๋Š” ๊ณ„๋ฅ˜๋ ฅ๋„ ์—ฌ๊ธฐ์— ํฌํ•จ๋œ๋‹ค. ์ฆ‰,

(2)
$F = F_{t}+ F_{f}+ F_{a}+ F_{m}$

์—ฌ๊ธฐ์„œ, $F_{t}$๋Š” ์—ฐ๊ฒฐ๋ถ€์— ์ž‘์šฉํ•˜๋Š” ํƒ€์›Œ ํ•˜๋‹จ์˜ ๋ฐ˜๋ ฅ, $F_{f}$๋Š” ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ, $F_{a}$๋Š” ์ง€์ง€๊ตฌ์กฐ์— ์ง์ ‘ ์ž‘์šฉํ•˜๋Š” ํ’๋ ฅ, $F_{m}$์€ ๊ณ„๋ฅ˜๋ผ์ธ์— ์˜ํ•œ ํ•˜์ค‘์ด๋‹ค.

์ƒ์„ธ ์„ค๊ณ„๋ฅผ ์œ„ํ•ด์„œ๋Š” ์‹œ๊ฐ„ ์˜์—ญ ํ•ด์„์„ ์ˆ˜ํ–‰ํ•˜๋„๋ก ์š”๊ตฌ๋˜๊ณ  ์žˆ๊ธฐ ๋•Œ๋ฌธ์—, ๋ชจ๋“  ์ž์œ ๋„๋ฅผ ์ง์ ‘ ๊ณ ๋ คํ•˜๋Š” ๋Œ€์‹  ๋ชจ๋‹ฌ ํ•ด์„ ๊ธฐ๋ฒ•(Modal analysis method)์„ ์ฑ„ํƒํ•ด์„œ ํ•ด์„์— ํ•„์š”ํ•œ ์‹œ๊ฐ„๊ณผ ๋น„์šฉ์„ ์ค„์ด๊ณ  ์žˆ๋‹ค.

2.2.3 ํ•ด์–‘ ์™ธ๋ ฅ๊ณผ ์ง€์ง€๊ตฌ์กฐ์™€์˜ ๋™์  ์ƒํ˜ธ์ž‘์šฉ

ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ์€ ์กฐ๋ฅ˜์™€ ํŒŒ๋ž‘์— ์˜ํ•ด ๋ฐœ์ƒํ•œ๋‹ค. ์กฐ๋ฅ˜์™€ ํŒŒ๋ž‘์˜ ์ง„ํ–‰๊ณผ ์ƒํ˜ธ ์ž‘์šฉํ•˜๋Š” ๊ตฌ์กฐ๋ฌผ์—๋Š” ์ด์— ์˜ํ•œ ์••๋ ฅ์ด ๋ฐœ์ƒํ•˜๋ฉฐ, ์ด ์••๋ ฅ์€ ๊ตฌ์กฐํ•ด์„ ์‹œ ๋ฐ˜๋“œ์‹œ ๊ณ ๋ ค๋˜์–ด์•ผ ํ•œ๋‹ค(Naess and Moan, 2019). ์‹ค์ œ๋กœ ๊ณ ์ •์‹ ๋ฐ ๋ถ€์œ ์‹ ๋ชจ๋‘ ๊ณต๋ ฅ๋ณด๋‹ค๋Š” ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ์ด ๊ตฌ์กฐ๋ฌผ ๊ฑฐ๋™์— ๋” ์ง€๋ฐฐ์ ์ธ ์˜ํ–ฅ์„ ๋ผ์นœ๋‹ค(Moriarty and Hansen, 2005). ์ด ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ์— ์˜ํ•œ ํ•˜์ค‘์€ ์‹ (2)์˜ $F_{f}$ ํ•ญ์œผ๋กœ ํ•ด์„์— ํฌํ•จ๋œ๋‹ค.

๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋Š” ๊ตฌ์กฐ๋ฌผ์˜ ์›€์ง์ž„์ด ์ƒ๋Œ€์ ์œผ๋กœ ์ž‘๊ณ , ์„ธ์žฅํ•œ ๋ถ€์žฌ๋กœ ๊ตฌ์„ฑ๋œ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฝ์šฐ์—๋Š” ๋‹ค์Œ ๋ชจ๋ฆฌ์Šจ ๋ฐฉ์ •์‹(Morison equation)์„ ์ด์šฉํ•ด์„œ ํ•ด์„œ ๋ถ€์žฌ์— ์ž‘์šฉํ•˜๋Š” ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ์„ ํ•˜์ค‘์„ ๊ณ„์‚ฐํ•œ๋‹ค(Cheng et al., 2019).

(3)
$F=\rho C_{M}V\dot{u}+\dfrac{1}{2}\rho C_{D}Au | u |$

์—ฌ๊ธฐ์„œ, $\rho$๋Š” ์œ ์ฒด์˜ ๋ฐ€๋„, $u$๋Š” ์œ ์ฒด์ž…์ž์˜ ์ˆ˜ํ‰ ์†๋„, $\dot{u}$๋Š” ์œ ์ฒด์ž…์ž์˜ ์ˆ˜ํ‰ ๊ฐ€์†๋„,$V$๋Š” ๋ถ€์žฌ์˜ ๋ถ€ํ”ผ, $C_{M}$๋Š” ์งˆ๋Ÿ‰๋ ฅ ๊ณ„์ˆ˜, $C_{D}$๋Š” ํ•ญ๋ ฅ ๊ณ„์ˆ˜, $A$๋Š” ๋ถ€์žฌ์˜ ํˆฌ์˜๋ฉด์ ์ด๋‹ค.

๋ชจ๋ฆฌ์Šจ ๋ฐฉ์ •์‹์€ ํ•ด์–‘ ๊ตฌ์กฐ๋ฌผ์˜ ๋‹จ๋ฉด ์ง๊ฒฝ์ด ํŒŒ์žฅ์— ๋น„ํ•ด ํฐ ๊ฒฝ์šฐ๋Š” ์ ์šฉ์ด ๋ถˆ๊ฐ€๋Šฅํ•˜๋‹ค. ๋ชจ๋ฆฌ์Šจ ๋ฐฉ์ •์‹์€ $D/L <0.2$ ๋ฒ”์œ„์—์„œ ์‚ฌ์šฉํ•˜๋Š” ๊ฒƒ์ด ์ผ๋ฐ˜์ ์ด๋‹ค. ์—ฌ๊ธฐ์„œ $D$๋Š” ๋ถ€์žฌ์˜ ์ง๊ฒฝ, $L$์€ ํŒŒ์žฅ์˜ ๊ธธ์ด์ด๋‹ค. ๋ชจ๋ฆฌ์Šจ ๋ฐฉ์ •์‹์— ์˜ํ•œ ํŒŒ์••์€ ๊ตฌ์กฐ๋ฌผ์˜ ์†๋„์— ๋Œ€ํ•œ ํ•จ์ˆ˜์ด๊ธฐ ๋•Œ๋ฌธ์— ์‹ (2)์˜ ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ๋„ $F_{f}= F_{f}(\dot{u)}$๋กœ ์ž‘์„ฑ๋œ๋‹ค.

2.3 ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ

๋ธ”๋ ˆ์ด๋“œ ๋ฐ ํ„ฐ๋นˆ์˜ ๊ณต๋ ฅ๊ฑฐ๋™๊ณผ ์ง€์ง€๊ตฌ์กฐ์˜ ๊ตฌ์กฐ๋™์—ญํ•™๊ฑฐ๋™์€ ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ๊ณผ ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ ๋ชจ๋‘ ๊ณ„์‚ฐ ๋ฐฉ๋ฒ•์ด ๊ฐ™๋‹ค. ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ์€ ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ๊ณผ ๋‹ฌ๋ฆฌ ํ•ด์–‘ ์™ธ๋ ฅ๊ณผ ์ง€์ง€๊ตฌ์กฐ์™€์˜ ๋™์  ์ƒํ˜ธ์ž‘์šฉ ๊ณ„์‚ฐ ์‹œ ํฌํ…์…œ ์ด๋ก ์„ ์ ์šฉํ•˜๋ฉฐ ๊ตฌ์กฐํ•ด์„ ์‹œ ๊ณ„๋ฅ˜๋ผ์ธ์˜ ํ•ด์„์„ ํฌํ•จํ•œ๋‹ค.

2.3.1 ํ•ด์–‘ ์™ธ๋ ฅ๊ณผ ์ง€์ง€๊ตฌ์กฐ์™€์˜ ๋™์  ์ƒํ˜ธ์ž‘์šฉ

๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ๋Š” ๋ถ€๋ ฅ์„ ํ™•๋ณดํ•˜๊ธฐ ์œ„ํ•œ ๋ถ€์œ ์ฒด๊ฐ€ ์‚ฌ์šฉ๋˜๊ธฐ ๋•Œ๋ฌธ์— ๋ชจ๋ฆฌ์Šจ ๋ฐฉ์ •์‹์œผ๋กœ๋Š” ํ•ด์–‘ ์™ธ๋ ฅ์„ ์ ์ ˆํ•˜๊ฒŒ ์‚ฐ์ •ํ•˜๋Š” ๊ฒƒ์ด ์–ด๋ ต๋‹ค. Waris and Ishihara(2012)๊ฐ€ ๋ถ€์œ ์ฒด์— ์ž‘์šฉํ•˜๋Š” ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ์„ ๋ชจ๋ฆฌ์Šจ ๋ฐฉ์ •์‹์œผ๋กœ ๊ณ„์‚ฐํ•œ ์‚ฌ๋ก€๊ฐ€ ์žˆ๊ธฐ๋Š” ํ•˜์ง€๋งŒ, ์ผ๋ฐ˜์ ์œผ๋กœ ์ธ์ •๋˜๋Š” ๊ธฐ๋ฒ•์€ ์•„๋‹ˆ๋‹ค. ๋ถ€์œ ์ฒด์™€ ํ•ด์–‘ ํ™˜๊ฒฝ์˜ ์ƒํ˜ธ์ž‘์šฉ์€ ์ผ์ข…์˜ FSI (Fluid structure interaction)๋ฌธ์ œ๋กœ์„œ ์ •๋ฐ€ํ•œ ํ•ด์„์€ ๋งค์šฐ ๋†’์€ ์ˆ˜์ค€์˜ ๋…ธ๋ ฅ์ด ํ•„์š”ํ•˜๋‹ค.

ํ•ด์–‘ ํ™˜๊ฒฝ์„ ํฌํ…์…œ ํ๋ฆ„์œผ๋กœ ๊ฐ€์ •ํ•˜๋ฉด ์œ ์ฒด์˜ ์†๋„๋Š” ํฌํ…์…œ์˜ ๋ฏธ๋ถ„์œผ๋กœ ์–ป์„ ์ˆ˜ ์žˆ์œผ๋ฉฐ, ํŒŒ์•• ๋˜ํ•œ ๋‹ค์Œ๊ณผ ๊ฐ™์ด ๊ณ„์‚ฐ๋œ๋‹ค. ์‹ (4a), (4b), (4c)์€ ๊ฐ๊ฐ ํฌํ…์…œ ํ๋ฆ„ ์ง€๋ฐฐ ๋ฐฉ์ •์‹, ํฌํ…์…œ๊ณผ ์œ ์ฒด ์†๋„ ์‹, ํฌํ…์…œ ์ด๋ก ์˜ ํŒŒ์•• ๊ณ„์‚ฐ์‹์ด๋‹ค.

(4a)
$\nabla\times\phi = 0$
(4b)
$V=\nabla\phi =\dfrac{\partial\phi}{\partial x}bold i +\dfrac{\partial\phi}{\partial y}bold j +\dfrac{\partial\phi}{\partial z}bold k$
(4c)
$p=\rho\dfrac{\partial\phi}{\partial t}$

์—ฌ๊ธฐ์„œ, $V$๋Š” ์œ ์ฒด์˜ ์†๋„, $\phi$๋Š” ์œ ์ฒด์˜ ํฌํ…์…œ์ด๋‹ค(Hong and Hong, 2013).

์‹ (4)์˜ ์„ ํ˜• ํฌํ…์…œ์€ Fig. 2์™€ ๊ฐ™์ด ์ดˆ๊ธฐ ํฌํ…์…œ, ํšŒ์ ˆ ํฌํ…์…œ, ๋ฐฉ์‚ฌ ํฌํ…์…œ์˜ ํ•ฉ์œผ๋กœ ํ‘œํ˜„๋œ๋‹ค. ์ฆ‰,

(5)
$\phi =\phi_{i}+\phi_{l}+\phi_{r}$

์—ฌ๊ธฐ์„œ, $\phi_{i}$๋Š” ์ดˆ๊ธฐ ํฌํ…์…œ(Incident potential), $\phi_{l}$์€ ํšŒ์ ˆ ํฌํ…์…œ(Reflection potential), $\phi_{r}$์€ ๋ฐฉ์‚ฌ ํฌํ…์…œ(Radiation potential)์ด๋‹ค. ์ดˆ๊ธฐ ํฌํ…์…œ์€ ์ง€์ง€๊ตฌ์กฐ ๋“ฑ๊ณผ ์ƒํ˜ธ์ž‘์šฉ์ด ์—†์ด ํŒŒ๋ž‘์ด ์ง„ํ–‰ํ•˜๋Š” ์›€์ง์ž„์— ๋Œ€ํ•œ ํฌํ…์…œ์ด๊ณ , ํšŒ์ ˆ ํฌํ…์…œ์€ ํŒŒ๋ž‘์ด ์ •์ง€ํ•œ ๊ตฌ์กฐ๋ฌผ์— ๋„๋‹ฌํ–ˆ์„ ๋•Œ ์œ ๋ฐœ๋˜๋Š” ํฌํ…์…œ์ด๋ฉฐ, ๋ฐฉ์‚ฌ ํฌํ…์…œ์€ ๊ตฌ์กฐ๋ฌผ์˜ ์›€์ง์ž„์— ์˜ํ•ด ์ƒ์„ฑ๋˜๋Š” ํฌํ…์…œ์ด๋‹ค. ๊ฐ ํฌํ…์…œ์— ํ•ด๋‹นํ•˜๋Š” ๊ฒฝ๊ณ„ ์กฐ๊ฑด์ด ์ ์šฉ๋˜์–ด์•ผ ํ•œ๋‹ค.

ํŒŒ์•• ๊ณ„์‚ฐ์„ ์œ„ํ•ด ํฌํ…์…œ ์ด๋ก ์„ ์ฑ„ํƒํ•˜๋Š” ๊ฒฝ์šฐ ์‹ (2)์˜ ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ์ด ํฌํ…์…œ๊ณผ ์กฐํ•ฉ๋˜๋ฏ€๋กœ $F_{f}= F_{f}(\phi)$๋กœ ์ˆ˜์ •๋œ๋‹ค. ๊ทธ๋Ÿฌ๋ฏ€๋กœ ์ด ๊ฒฝ์šฐ ์‹ (2)์™€ ์‹ (4a)๋ฅผ ์—ฐ์„ฑํ•˜์—ฌ ํ’€์–ด์•ผ ํ•œ๋‹ค. ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ์€ ํฌํ…์…œ ์ด๋ก ์—์„œ ๊ณ„์‚ฐํ•œ ํŒŒ์•• $p(\phi)$์„ ์ง€์ง€๊ตฌ์กฐ ํ‘œ๋ฉด $\gamma$์„ ๋”ฐ๋ผ ์ ๋ถ„ํ•œ ๊ฐ’์ด๋‹ค.

(6)
$F_{f}=\int_{\gamma}p(\phi)d\gamma$
Fig. 2 Conceptual diagram of Interaction between potential flow and floating structure
../../Resources/ksm/jksmi.2023.27.4.33/fig2.png

2.3.2 ๊ณ„๋ฅ˜๋ผ์ธ์˜ ๋™์  ๊ฑฐ๋™

์ผ๋ถ€ ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋„ ๊ณ„๋ฅ˜๋ผ์ธ์„ ์„ค์น˜ํ•ด์„œ ์ง€์ง€๊ตฌ์กฐ์˜ ์ œ์ž‘ ๋น„์šฉ์„ ์ ˆ๊ฐํ•˜๋Š” ์•ˆ๋„ ์žˆ์œผ๋‚˜, ์‹ค์ œ ์‚ฌ์—…์— ์ ์šฉ๋˜๋Š” ๊ฒฝ์šฐ๋Š” ๋งค์šฐ ๋“œ๋ฌผ๋‹ค. ๊ตญ๋‚ด ํ•ด์–‘์—์„œ ๊ฐœ๋ฐœ ํ–‰์œ„๋ฅผ ์œ„ํ•ด์„œ๋Š” ๊ณต์œ ์ˆ˜๋ฉด ์ ์‚ฌ์šฉ ํ—ˆ๊ฐ€๋ฅผ ์ทจ๋“ํ•ด์•ผ ํ•˜๋Š”๋ฐ, ๊ณ„๋ฅ˜๋ผ์ธ์ด ์„ค์น˜๋˜๋Š” ๋ฒ”์œ„๊นŒ์ง€ ๋Œ€์ƒ ํ•ด์—ญ์ด ์„ค์ •๋˜๋ฏ€๋กœ ์ด ๋น„์šฉ์˜ ์ฆ๊ฐ€๊ฐ€ ์‚ฌ์—… ๋น„์šฉ์— ์ถ”๊ฐ€๋œ๋‹ค. ๊ทธ๋Ÿฌ๋ฏ€๋กœ ๊ตญ๋‚ด์—์„œ ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ์— ๊ณ„๋ฅ˜๋ผ์ธ์„ ์„ค์น˜ํ•˜๋Š” ๊ฒƒ์€ ๊ฑฐ์˜ ๋ถˆ๊ฐ€๋Šฅํ•œ ์•„์ด๋””์–ด์ด๋‹ค.

Fig. 3์€ ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ์˜ ์œ„์น˜๋ฅผ ํ™•๋ณดํ•˜๊ธฐ ์œ„ํ•ด ์„ค์น˜ํ•œ ๊ณ„๋ฅ˜๋ผ์ธ๊ณผ ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ์˜ ์ƒํ˜ธ์ž‘์šฉ์˜ ๊ฐœ๋…๋„์ด๋‹ค. ์œ ์ผํ•œ ๋ถ€์œ ์‹ ํ•ด์ƒํ’๋ ฅ ์‚ฌ๋ก€์ธ ํ•˜์ด์œˆ ์Šค์ฝ”ํŠธ๋žœ๋“œ ๋ถ€์œ ์‹ ํ•ด์ƒํ’๋ ฅ ๋‹จ์ง€์— ์„ค์น˜๋œ 6MW ๋ถ€์œ ์‹ ํ•ด์ƒํ’๋ ฅ ๋ฐœ์ „๊ธฐ์˜ ์ง€์ง€๊ตฌ์กฐ์— ์„ค์น˜๋œ ๊ณ„๋ฅ˜๋ผ์ธ๋„ ๊ฑฐ์˜ 600m ์ด์ƒ์˜ ๊ฑฐ๋ฆฌ๊นŒ์ง€ ์—ฐ์žฅ๋˜์–ด ์„ค์น˜๋œ๋‹ค(Scottish Government, 2017). ๊ณ„๋ฅ˜๋ผ์ธ์ด ์„ค์น˜๋˜์–ด๋„ ํ•ด์–‘ ํ™˜๊ฒฝ๊ณผ ์ƒํ˜ธ์ž‘์šฉ์— ์˜ํ•ด 10m ์ด์ƒ์˜ ์ง€์ง€๊ตฌ์กฐ ์œ„์น˜ ๋ณ€์œ„๊ฐ€ ๋™์ ์œผ๋กœ ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค. ๊ณ„๋ฅ˜๋ผ์ธ์€ Fig. 4์™€ ๊ฐ™์ด ์ดˆ๊ธฐ ๊ธด์žฅ๋ ฅ ๋ฟ ๋งŒ ์•„๋‹ˆ๋ผ ์ž์ค‘, ๋ถ€๋ ฅ, ์กฐ๋ฅ˜๋ ฅ๊ณผ ํŒŒ๋ž‘ ํ•˜์ค‘์ด ์ž‘์šฉํ•˜๋Š” ๋น„์„ ํ˜•๋ฌธ์ œ์ด๋‹ค(Jung et al., 2019).

๋”์šฑ์ด ๊ณ„๋ฅ˜๋ผ์ธ์˜ ๊ฐ•์„ฑ์ด ์ง€์ง€๊ตฌ์กฐ์˜ ๊ฐ•์„ฑ์— ๋น„ํ•ด ๋งค์šฐ ์ž‘๊ธฐ ๋•Œ๋ฌธ์— ์‹ (1)์˜ ์ง€์ง€๊ตฌ์กฐ ์ „์ฒด์˜ ๊ฐ•์„ฑ์— ๊ณ„๋ฅ˜๋ผ์ธ์„ ๊ณ ๋ คํ•˜๋Š” ๊ฒƒ์€ ๋งค์šฐ ๋ณต์žกํ•˜๋ฉฐ ์ˆ˜๋ ด์„ฑ ๋ฌธ์ œ๋ฅผ ์œ ๋ฐœํ•  ์ˆ˜ ์žˆ๋‹ค. ๋Œ€์‹  ์‹ (2)์˜ ์šฐ์ธก ํ•ญ์— ์ง€์ง€๊ตฌ์กฐ์˜ ๋ณ€์œ„์™€ ์†๋„์˜ ํ•จ์ˆ˜๋กœ ๊ณ„๋ฅ˜๋ ฅ ๊ณ„์‚ฐํ•œ๋‹ค, ์ฆ‰ $F_{m}= F_{m}(u,\: \dot{u})$๋กœ ๊ณ„์‚ฐํ•œ๋‹ค. ๋˜ํ•œ, ๊ณ„๋ฅ˜์„  ๊ฑฐ๋™์˜ ๋น„์„ ํ˜• ๋•Œ๋ฌธ์— ๋ณ„๋„์˜ ๋ชจ๋“ˆ๋กœ ์ž‘์„ฑํ•˜๋Š” ๊ฒƒ์ด ์ผ๋ฐ˜์ ์ด๋‹ค. ์ž์ค‘, ๋ถ€๋ ฅ ์กฐ๋ฅ˜๋ ฅ์˜ ์—ฌ๋Ÿฌ ํ•˜์ค‘๋“ค์ด ์ž‘์šฉํ•˜๋Š” ๊ณ„๋ฅ˜๋ผ์ธ์˜ ๊ธด์žฅ๋ ฅ($F$ )์€ ๊ณ„๋ฅ˜๋ผ์ธ์˜ ๋‹จ๋ฉด์ $A$, ๊ณ„๋ฅ˜๋ผ์ธ์˜ ๊ธธ์ด($L$), ํƒ„์„ฑ ๊ณ„์ˆ˜($E$ ), ์œ ์ฒด ๋‚ด์—์„œ์˜ ๋‹จ์œ„ ๊ธธ์ด๋‹น ์ž์ค‘($w$), ๊ณ„๋ฅ˜๋ผ์ธ์˜ ์ˆ˜ํ‰์„ฑ๋ถ„ ๊ธธ์ด($l$), ๊ณ„๋ฅ˜๋ผ์ธ์˜ ์ˆ˜์ง์„ฑ๋ถ„ ๊ธธ์ด($h$)๋ฅผ ํ†ตํ•ด ๊ตฌํ•  ์ˆ˜ ์žˆ๋‹ค. ์ด์— ๋Œ€ํ•œ ๊ตฌ์ฒด์ ์ธ ์‹์€ ํ•˜๋‹จ ๊ฐ์ฃผ์—์„œ ๋ณด์ด๊ณ  ์žˆ๋‹ค(National Renewable Energy Laboratory, 2017).

(7)
$F = f(L,\: E,\: w,\: l,\: h)$
Fig. 3 Conceptual diagram of floating support structures and mooring line behaviors
../../Resources/ksm/jksmi.2023.27.4.33/fig3.png
Fig. 4 Load acting on a unit mooring line
../../Resources/ksm/jksmi.2023.27.4.33/fig4.png

1) ๊ณ„๋ฅ˜๋ผ์ธ์˜ ๊ธด์žฅ๋ ฅ

$l =\dfrac{F_{1}}{w}\left\{\ln\left[\dfrac{F_{2}}{F_{1}}+\sqrt{1+\left(\dfrac{F_{2}}{F_{1}}\right)^{2}}\right]-\ln\left(\dfrac{F_{2}-w L}{F_{1}}+\right .\right .$$\left .\left .\sqrt{1+\left(\dfrac{F_{2}-w L}{F_{1}}\right)^{2}}\right)\right\}+\dfrac{F_{2}L}{EA}$

$h =\dfrac{F_{1}}{w}\left\{\sqrt{1+\left(\dfrac{F_{2}}{F_{1}}\right)^{2}}-\sqrt{1+\left(\dfrac{F_{2}-w L}{F_{1}}\right)^{2}}\right\}+\dfrac{1}{EA}\left(F_{2}L-\dfrac{w L^{2}}{2}\right)$

$F_{3}= F_{1}$

$F_{4}= F_{2}-w L$

์—ฌ๊ธฐ์„œ $F_{1}$, $F_{2}$, $F_{3}$, $F_{4}$์€ Fig. 4์™€ ๊ฐ™์ด ์™ธ๋ถ€ํ•˜์ค‘์ด ์ž‘์šฉํ•˜๋Š” ๊ณ„๋ฅ˜๋ผ์ธ์˜ ์ˆ˜ํ‰ ๋ฐ ์ˆ˜ํ‰์„ฑ๋ถ„ ๊ธด์žฅ๋ ฅ์ด๋‹ค.

3. ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ ํ•ด์„ ์‹ค๋ฌด

3.1 ํ˜„ ์‹ค๋ฌด์—์„œ ์ฑ„ํƒํ•˜๋Š” ํ•ด์„ ์ ˆ์ฐจ

ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ์˜ ๋‹ค์ค‘๋ฌผ๋ฆฌ ํŠน์„ฑ ๋•Œ๋ฌธ์— ํ•ด์„ ๊ธฐ๋ฒ•์„ ๊ฐœ๋ฐœํ•˜๋Š” ์—ฐ๊ตฌ๋Š” ์ตœ๊ทผ๊นŒ์ง€๋„ ์ง„ํ–‰ํ˜•์ด๋‹ค(Kim et al., 2019; Lee and Bea, 2019; Lee et al., 2018; Lee et al., 2016;Kim and Lee, 2012). ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ๊ณผ ๊ตฌ์กฐ๋ฌผ์˜ ๊ฐ•์ฒด ๊ฑฐ๋™์„ ์—ฐ์„ฑํ•˜๋Š” ๊ธฐ๋ฒ•์€ WAMIT์œผ๋กœ ๊ตฌํ˜„๋œ Wu์˜ ๊ธฐ๋ฒ•์ด ๊ฑฐ์˜ ํ‘œ์ค€์œผ๋กœ ์‚ฌ์šฉ๋˜๊ณ  ์žˆ๋‹ค(Lee and Newman, 2006). Wu์˜ ๊ธฐ๋ฒ•์—์„œ, ์ž‘์€ ์šฉ๋Ÿ‰์˜ ์ง€์ง€๊ตฌ์กฐ๋Š” ๊ตฌ์กฐ๋ฌผ์˜ ๋ณ€ํ˜•์ด ์ž‘์•„์„œ ๊ตฌ์กฐ๋ฌผ์˜ ํƒ„์„ฑ๋ณ€ํ˜•์€ ๋ฌด์‹œํ•  ์ˆ˜ ์žˆ๋‹ค(Waris, 2009). ์ตœ๊ทผ ๊ฐœ๋ฐœ์ด ์ถ”์ง„๋˜๊ณ  ์žˆ๋Š” 10-15MW๊ธ‰์˜ ๋Œ€ํ˜• ์ง€์ง€๊ตฌ์กฐ๋ฌผ์„ ํ•ด์„ํ•  ๋•Œ๋Š” ๊ตฌ์กฐ๋ฌผ์˜ ํƒ„์„ฑ ๋ณ€ํ˜•๋„ ๊ฑฐ๋™์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๋Š” ์ฃผ์š” ์ธ์ž๋กœ ๊ณ ๋ คํ•  ํ•„์š”๊ฐ€ ์žˆ์œผ๋‚˜ ์ด์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋Š” ์•„์ง๋„ ์ง„ํ–‰์ค‘์ด๋‹ค. ์ฃผํŒŒ์ˆ˜ ์˜์—ญ์—์„œ ์ผ๋ถ€ ์—ฐ๊ตฌ๋œ ์‚ฌ๋ก€๊ฐ€ ์žˆ์œผ๋‚˜ ์•„์ง ์‹œ๊ฐ„์˜์—ญ์˜ ๊ฑฐ๋™๊นŒ์ง€ ํ™•์žฅ๋˜์ง€๋Š” ์•Š๊ณ  ์žˆ๋‹ค(Lamei and Hayatdavoodi, 2009).

๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋„ ๊ตฌ์กฐ๋ฌผ์˜ ๋ณ€์œ„๋ฅผ ์˜์œผ๋กœ ๊ทผ์‚ฌํ™”ํ•˜์—ฌ ์‹ (1)์˜ ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ $F_{f}$์™€ ๊ณต๋ ฅ ํ•˜์ค‘ $F_{a}$๋ฅผ ๊ตฌ์กฐ๋ฌผ์˜ ๊ฑฐ๋™๊ณผ๋Š” ๋…๋ฆฝ์ ์œผ๋กœ ์ „์ฒด ์‹œ๊ฐ„ ์˜์—ญ์—์„œ ๊ณ„์‚ฐํ•œ ํ›„, ์ด ํ•˜์ค‘์„ ์ง€์ง€๊ตฌ์กฐ์— ๊ฐ€๋ ฅํ•˜์—ฌ ๋™์ ์ธ ํ•ด์„์„ ์ˆ˜ํ–‰ํ•˜๋Š” ๋ฐฉ์‹์œผ๋กœ ์‹ค๋ฌด๋ฅผ ์ˆ˜ํ–‰ํ•˜๊ณ  ์žˆ๋‹ค(Pham, 2022; Parkinson and Han, 2022).

๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ์˜ ๊ฒฝ์šฐ๋Š” ๋” ๋ณต์žกํ•œ ํ•ด์„ ํ๋ฆ„์„ ๋”ฐ๋ผ ๋‹ค์ˆ˜์˜ ์†Œํ”„ํŠธ์›จ์–ด๊ฐ€ ์ˆœ์ฐจ์ ์œผ๋กœ ์‚ฌ์šฉ๋œ๋‹ค. ์šฐ์„  ๊ฐ•์ฒดํ™”๋œ ์ง€์ง€๊ตฌ์กฐ์™€ ํ•ด์–‘ ํ™˜๊ฒฝ ์™ธ๋ ฅ์„ ์—ฐ์„ฑํ•˜์—ฌ ์‹ (1)์— ํ•ด์–‘ ํ™˜๊ฒฝ์˜ ํšจ๊ณผ๊ฐ€ ๋ฐ˜์˜๋˜๋„๋ก ์ˆ˜์ •ํ•œ๋‹ค.

(8)
$(M+M_{f})\ddot{u}+(C+C_{f})\dot{u}+(K+K_{f})u = F$

์—ฌ๊ธฐ์„œ, $M_{f}$๋Š” ๋ถ€๊ฐ€์งˆ๋Ÿ‰(Added mass), $C_{f}$๋Š” ๋ถ€๊ฐ€๊ฐ์‡„(Added damping), $K_{f}$๋Š” ๋ถ€๊ฐ€๊ฐ•์„ฑ(Added stiffness)์ด๋‹ค. ์ด ๋ถ€๊ฐ€ํ•ญ๋“ค์€ ์ง€์ง€๊ตฌ์กฐ์˜ ์›€์ง์ž„์— ๊ฐœ์ž…ํ•˜๋Š” ์œ ์ฒด์˜ ์˜ํ–ฅ์„ ๊ณ ๋ คํ•˜๋Š” ํ•ญ์œผ๋กœ์„œ ์ฃผํŒŒ์ˆ˜ ์˜์—ญ์—์„œ ๋ณ„๋„๋กœ ๊ณ„์‚ฐ๋œ๋‹ค.

์‹ (7)๊ณผ ๋ธ”๋ ˆ์ด๋“œ-ํƒ€์›Œ ๋ชจ๋“ˆ์„ ์—ฐ์„ฑํ•˜์—ฌ ์ง€์ง€๊ตฌ์กฐ์˜ ๋ณ€์œ„๋ฅผ ๊ณ„์‚ฐํ•œ ํ›„, ์ด์— ํ•ด๋‹นํ•˜๋Š” ํƒ€์›Œ ํ•˜๋‹จ ๋ฐ˜๋ ฅ $F_{t}$, ๊ณ„๋ฅ˜๋ ฅ $F_{m}$, ํŒŒ์•• $p$์„ ๋ณ„๋„์˜ ์†Œํ”„ํŠธ์›จ์–ด๋กœ ๊ณ„์‚ฐํ•œ๋‹ค. ๊ทธ ๋‹ค์Œ ๋‹จ๊ณ„๋กœ์„œ ์ง€์ง€๊ตฌ์กฐ ๋งŒ์„ ๋Œ€์ƒ์œผ๋กœ ์‘๋ ฅ์„ ๊ณ„์‚ฐํ•œ๋‹ค.

์ „์ˆ ํ•œ ์ ˆ์ฐจ์˜ ๋‹จ๊ณ„ ๋ณ„๋กœ SACS, MOSES, SESAM, BLADED, OpenFAST ๋“ฑ์„ ์‹ค๋ฌด์—์„œ ์‚ฌ์šฉํ•˜๊ณ  ์žˆ๋‹ค.

3.2 SACS์™€ MOSES๋ฅผ ์กฐํ•ฉํ•œ ํ•ด์„

SACS๋Š” ํ•ด์–‘ ๊ตฌ์กฐ๋ฌผ์˜ ํ•ด์„๊ณผ ์„ค๊ณ„์— ๊ฐ€์žฅ ๋„๋ฆฌ ์‚ฌ์šฉ๋˜๋Š” ์œ ํ•œ์š”์†Œ ๊ธฐ๋ฐ˜์˜ ํ•ด์„ ์†Œํ”„ํŠธ์›จ์–ด์ด๋‹ค. ํ•ด์„์˜ ๊ธฐ๋Šฅ ๋ฟ ๋งŒ ์•„๋‹ˆ๋ผ ์ฃผ์š” ํ•˜์ค‘์กฐํ•ฉ์— ๋Œ€ํ•œ ๊ธฐ์ค€ํ•ญ๋ชฉ์„ ๊ฒ€ํ† ํ•  ์ˆ˜๋„ ์žˆ๋‹ค. MOSES๋Š” ํ•ด์–‘ ํ™˜๊ฒฝ ์กฐ๊ฑด์„ ์ฃผํŒŒ์ˆ˜ ์˜์—ญ๊ณผ ์‹œ๊ฐ„์˜์—ญ์—์„œ ๊ณ ๋ คํ•  ์ˆ˜ ์žˆ์œผ๋ฉฐ, ๊ฐ•์ฒด์˜ ์›€์ง๊ณผ ๊ณ„๋ฅ˜์„ ์˜ ๊ฑฐ๋™์„ ํ•ด์„ํ•  ์ˆ˜ ์žˆ๋‹ค. Fig. 5๋Š” MOSES์™€ SACS๋ฅผ ์กฐํ•ฉํ•˜์—ฌ ๋ถ€์œ ์‹ ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ ํ•ด์„์— ์‚ฌ์šฉํ•˜๋Š” OpenWind Power ์†Œํ”„ํŠธ์›จ์–ด์˜ ๊ตฌ๋™ ๊ฐœ๋…๋„์ด๋‹ค(Pham, 2022).

(1) ์šฐ์„  MOSES์—์„œ ํ•ด์–‘ ํ™˜๊ฒฝ ์กฐ๊ฑด์˜ ๊ฐ•์ฒด ํ•ด์„์„ ์ˆ˜ํ–‰ํ•˜๊ณ , (2) ์ง€์ง€๊ตฌ์กฐ์˜ ๋ณ€์œ„ ์ •๋ณด๋ฅผ ๋ธ”๋ ˆ์ด๋“œ-ํ„ฐ๋นˆ-ํƒ€์›Œ ๋ชจ๋“ˆ์— ์ „๋‹ฌํ•˜์—ฌ ํƒ€์›Œ ๋ฐ ํ„ฐ๋นˆ ์‹œ์Šคํ…œ์„ ํ•ด์„ํ•˜๊ณ , (3) ํƒ€์›Œ ํ•˜๋‹จ์˜ ๋ฐ˜๋ ฅ $F_{t}$, ๊ณ„๋ฅ˜๋ ฅ $F_{m}$, ์ง€์ง€๊ตฌ์กฐ์˜ ๊ฐ•์ฒด ๋ณ€์œ„๋ฅผ ๋‹ค์‹œ MOSES๋กœ ์ „๋‹ฌํ•˜์—ฌ ์‹œ๊ฐ„ ์˜์—ญ์˜ ํŒŒ์••์„ ๊ณ„์‚ฐํ•œ๋‹ค. (4) ์ด ํ•˜์ค‘๊ณผ ํŒŒ์••์„ ์ด์šฉํ•ด์„œ SACS์—์„œ ๊ตฌ์กฐ๋ฌผ์˜ ์‘๋ ฅ์„ ๊ณ„์‚ฐํ•˜๋Š” ๋ฐฉ์‹์œผ๋กœ ์ˆœ์ฐจ์ ์œผ๋กœ ๊ฐœ๋ณ„ ์†Œํ”„ํŠธ์›จ์–ด๋ฅผ ๊ตฌ๋™ํ•œ๋‹ค(Pham, 2022).

์ด ๊ณผ์ •์—์„œ ์„œ๋กœ ๋‹ค๋ฅธ ์†Œํ”„ํŠธ์›จ์–ด ์‹œ์Šคํ…œ ์‚ฌ์ด์—์„œ ๋ฐ์ดํ„ฐ ์ „๋‹ฌ์ด ํ•„์—ฐ์ ์œผ๋กœ ๋ฐœ์ƒํ•˜๋ฏ€๋กœ ํ•ด์„์— ํ•„์š”ํ•œ ์‹œ๊ฐ„๊ณผ ๋น„์šฉ์ด ํฌ๊ฒŒ ๋ฐœ์ƒํ•œ๋‹ค.

Fig. 5 Analysis procedure using SACS and MOSES
../../Resources/ksm/jksmi.2023.27.4.33/fig5.png

3.3 SESAM๊ณผ BLADED๋ฅผ ์กฐํ•ฉํ•œ ํ•ด์„

SESAM ๋˜ํ•œ SACS์™€ ์œ ์‚ฌํ•˜๊ฒŒ ์œ ํ•œ์š”์†Œ ๊ธฐ๋ฐ˜์œผ๋กœ ๊ฐœ๋ฐœ๋œ ํ•ด์–‘ํ”Œ๋žœํŠธ ์ „๋ฌธ ํ•ด์„ ์†Œํ”„ํŠธ์›จ์–ด์ด๋‹ค. SESAM ์—ญ์‹œ ์ž์ฒด์ ์œผ๋กœ ํ†ตํ•ฉํ•˜์ค‘ํ•ด์„์ด ๋ถˆ๊ฐ€๋Šฅํ•˜๋ฏ€๋กœ SESAM, BLADED, SIMA, WASIM ํ”„๋กœ๊ทธ๋žจ์„ ์กฐํ•ฉํ•˜์—ฌ ๋ถ€์œ ์‹ ๊ตฌ์กฐ๋ฌผ ํ•ด์„์„ ์ง„ํ–‰ํ•œ๋‹ค. Fig. 6๋Š” SESAM๊ณผ BLADED๋ฅผ ์กฐํ•ฉํ•œ ๋ถ€์œ ์‹ ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ ํ•ด์„ ๊ตฌ๋™ ๊ฐœ๋…๋„์ด๋‹ค(Parkinson and Han, 2022). (1) SESAM์—์„œ ์œ ์ฒด๋ ฅ ํ•ด์„์„ ์ง„ํ–‰ํ•˜๊ณ , (2) ํ•ด์„ํ•œ ์ •๋ณด๋ฅผ BLADED์— ์ „๋‹ฌํ•˜์—ฌ ์ง€์ง€๊ตฌ์กฐ-ํ„ฐ๋นˆ ํ†ตํ•ฉํ•˜์ค‘์„ ์ˆ˜ํ–‰ํ•˜๊ฑฐ๋‚˜, SIMA ๋ชจ๋“ˆ๊ณผ ์—ฐ๋™ํ•˜์—ฌ ์ง€์ง€๊ตฌ์กฐ-๊ณ„๋ฅ˜์„  ํ†ตํ•ฉํ•˜์ค‘์„ ์ˆ˜ํ–‰ํ•œ๋‹ค. (3) ํƒ€์›Œ ํ•˜๋‹จ์˜ ๋ฐ˜๋ ฅ $F_{t}$, ๊ณ„๋ฅ˜๋ ฅ $F_{m}$, ์ง€์ง€๊ตฌ์กฐ์˜ ๊ฐ•์ฒด ๋ณ€์œ„๋ฅผ WASIM์— ์ „๋‹ฌํ•˜์—ฌ ์‹œ๊ฐ„์˜์—ญ์˜ ํŒŒ์••์„ ๊ณ„์‚ฐํ•˜๊ณ  ๊ตฌ์กฐ๋ฌผ์— ๋งตํ•‘ํ•œ๋‹ค. (4) ์ด ํ•˜์ค‘์„ ๋‹ค์‹œ SESAM์— ์ „๋‹ฌํ•˜์—ฌ SESAM์—์„œ ๊ตฌ์กฐ๋ฌผ์˜ ์‘๋ ฅ์„ ๊ณ„์‚ฐํ•œ๋‹ค(Parkinson and Han, 2022).

์—ญ์‹œ ๋งˆ์ฐฌ๊ฐ€์ง€๋กœ ๊ฐœ๋ณ„ ๋ฌผ๋ฆฌ์—ฐ์‚ฐ ๋ชจ๋“ˆ ๊ฐ„์— ๋ฐ์ดํ„ฐ ์ „๋‹ฌ์ด ๋ถˆ๊ฐ€ํ”ผํ•˜๋ฏ€๋กœ, ํ•ด์„์˜ ๋ณต์žก๋„๊ฐ€ ์ฆ๊ฐ€ํ•œ๋‹ค.

Fig. 6 Analysis procedure using SESAM and BLADED
../../Resources/ksm/jksmi.2023.27.4.33/fig6.png
Fig. 7 Conceptual diagram of OpenFAST
../../Resources/ksm/jksmi.2023.27.4.33/fig7.png

3.4 OpenFAST๋ฅผ ์‚ฌ์šฉํ•œ ํ•ด์„

OpenFAST๋Š” ๋ฏธ๊ตญ ์‹ ์žฌ์ƒ์—๋„ˆ์ง€์—ฐ๊ตฌ์†Œ(NREL)์—์„œ ๊ฐœ๋ฐœํ•˜์—ฌ ๋ฐฐํฌํ•œ ์˜คํ”ˆ์†Œ์Šค ํŒจํ‚ค์ง€์ด๋ฉฐ, ๋ฌด๋ฃŒ๋กœ ์‚ฌ์šฉํ•  ์ˆ˜ ์žˆ๋‹ค. ๋‹จ์ผ ์†Œํ”„ํŠธ์›จ์–ด์ฒ˜๋Ÿผ ๋ณด์ด๋‚˜, Fig. 7๊ณผ ๊ฐ™์ด Aerodyn, Elastodyn, Hydrodyn, MAP++, Moordyn ๋“ฑ์ด ๊ธฐ๋Šฅ๋ณ„๋กœ ์—ฐ์„ฑ๋˜์–ด ์žˆ๋‹ค.๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ์˜ ํ•ด์„์€ Aerodyn, Elastodyn, Hydrodyn ๋“ฑ์„ ์‚ฌ์šฉํ•˜๊ณ  ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ์˜ ํ•ด์„์€ ์—ฌ๊ธฐ์— ๋”ํ•˜์—ฌ MAP++์™€ MoorDyn ๋“ฑ์„ ์‚ฌ์šฉํ•œ๋‹ค. ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ์˜ ํ•ด์„์šฉ์œผ๋กœ ๊ตญ์ œ์ ์œผ๋กœ ์‹ ๋ขฐ์„ฑ์ด ์ธ์ •๋˜์–ด ๋‹ค์–‘ํ•œ ๋ฌธํ—Œ์—์„œ ์ƒํ˜ธ ๊ฒ€์ฆ์šฉ์œผ๋กœ ํ™œ์šฉ๋˜๊ณ  ์žˆ๋‹ค. ๊ฐœ๋ฐฉ๋œ ๊ตฌ์กฐ์ด๋‚˜ ์ „ํ›„์ฒ˜๋ฆฌ๊ฐ€ ๊ฐœ๋ฐœ๋˜์ง€ ์•Š์•„์„œ ์ ์šฉ์„ฑ์ด ๊ทธ๋ฆฌ ๋†’์ง€๋Š” ์•Š๋‹ค(National Renewable Energy Laboratory, 2023).

Table 1๊ณผ ๊ฐ™์ด ํ•ด์ƒํ’๋ ฅ ํ•ด์„ ์‹ค๋ฌด์—์„œ ์‚ฌ์šฉ๋˜๋Š” ์†Œํ”„ํŠธ์›จ์–ด๋“ค์€ ๊ฐ๊ฐ ๊ณ ์œ ์˜ ์žฅ์ ๊ณผ ํ•œ๊ณ„๋ฅผ ๊ฐ€์ง„๋‹ค. SACS์™€ MOSES๋ฅผ ์กฐํ•ฉํ•˜๋Š” ๋ฐฉ์‹๊ณผ SESAM๊ณผ BLADED๋ฅผ ์กฐํ•ฉํ•˜๋Š” ๋ฐฉ์‹์€ ๋ชจ๋‘ ์ „ํ›„์ฒ˜๋ฆฌ๊ธฐ๋ฅผ ๊ฐ€์ง€๊ณ  ์žˆ์–ด ๋†’์€ ์‚ฌ์šฉ์„ฑ์„ ๋ณด์ด์ง€๋งŒ, ์„œ๋กœ ๋‹ค๋ฅธ ์†Œํ”„ํŠธ์›จ์–ด ์‹œ์Šคํ…œ ์‚ฌ์ด์˜ ๋ฐ์ดํ„ฐ ์ „๋‹ฌ์ด ํ•„์ˆ˜์ ์ด๋‹ค. OpenFAST๋Š” ๋ฐ์ดํ„ฐ ์ „๋‹ฌ ์—†์ด ๊ฐ™์€ ํ”„๋กœ๊ทธ๋žจ๋‚ด์—์„œ ํ•ด์„์ด ๊ฐ€๋Šฅํ•˜์ง€๋งŒ ์ „ํ›„์ฒ˜๋ฆฌ๊ธฐ ๋ฏธ๋น„๋กœ ์ ์šฉ์„ฑ์ด ๋‚ฎ๋‹ค.

Fig. 8 Works of drawing and analysis model generation, driven in its respective environment
../../Resources/ksm/jksmi.2023.27.4.33/fig8.png
Fig. 9 Integrated analysis procedure of X-WIND implemented in the AutoCAD environment
../../Resources/ksm/jksmi.2023.27.4.33/fig9.png
Table 1 Key features and limitations of offshore wind energy analysis softwares

Bentley

DNV-GL

NREL

Program

SACS

MOSES

SESAM

BLADED

Open FAST

Main Function

Offshore structure analysis

Hydroforce Calculation

Offshore structure analysis

Aerodynamic analysis

Analysis within a single program

Modelling

O

X

O

O

X

Aerodynamic analysis

X

X

X

O

O

Hydroforce and Mooring line analysis

X

O

O

X

O

Structure analysis

O

X

O

O

O

Pre-/Post-Processor

O

O

O

O

X

4. ์˜คํ† ์บ๋“œ ํ™˜๊ฒฝ์˜ ํ•ด์ƒํ’๋ ฅ ํ•ด์„ ์†Œํ”„ํŠธ์›จ์–ด ๊ฐœ๋ฐœ

4.1 ์„ค๊ณ„์šฉ ๊ฐ์ฒด์™€ ํ•ด์„์šฉ ๊ฐ์ฒด ํ™˜๊ฒฝ์˜ ์ฐจ์ด

๊ตฌ์กฐ๋ฌผ ์„ค๊ณ„์— ๋Œ€ํ•œ ์„ฑ๊ณผ๋Š” ๋„๋ฉด๊ณผ ๊ตฌ์กฐ๊ณ„์‚ฐ์„œ๋กœ ๋‚ฉํ’ˆ๋œ๋‹ค. ๋„๋ฉด์—๋Š” ๊ตฌ์กฐ๋ฌผ์˜ ๊ธฐํ•˜ํ•™์ ์ธ ์š”์†Œ๋“ค์ด ํ‘œํ˜„๋˜์ง€๋งŒ, ๊ตฌ์กฐ๊ณ„์‚ฐ์„œ์—๋Š” ํ•ด๋‹น ๊ตฌ์กฐ๋ฌผ์˜ ์—ญํ•™์ ์ธ ๊ฑฐ๋™์ด ๊ธฐ์ค€์น˜์™€ ๋น„๊ต๋˜๋Š” ๋‚ด์šฉ์ด ํฌํ•จ๋œ๋‹ค. ๋„๋ฉด์˜ ์ž‘์„ฑ์— ์‚ฌ์šฉ๋˜๋Š” ์†Œํ”„ํŠธ์›จ์–ด์™€ ๊ตฌ์กฐ๊ณ„์‚ฐ์„œ ์ž‘์„ฑ์šฉ์œผ๋กœ ๊ฒ€ํ† ๋ฅผ ์ˆ˜ํ–‰ํ•˜๋Š”๋ฐ ์‚ฌ์šฉ๋˜๋Š” ์†Œํ”„ํŠธ์›จ์–ด๋Š” ์ƒ์ดํ•œ ์•„ํ‚คํ…์ณ์— ๊ธฐ๋ฐ˜ํ•˜๊ณ  ์žˆ๋‹ค. ๋™์ผํ•œ ๋Œ€์ƒ ๊ตฌ์กฐ๋ฌผ์ด๋ผ๊ณ  ํ•ด๋„ Fig. 8๊ณผ ๊ฐ™์ด ๋„๋ฉด์šฉ ์†ŒํŠธ์›จ์–ด์™€ ํ•ด์„์šฉ ์†Œํ”„ํŠธ์›จ์–ด๋ฅผ ๋™์‹œ์— ์‚ฌ์šฉํ•ด์•ผ ํ•œ๋‹ค.

๊ตฌ์กฐ๋ฌผ ๊ฐ์ฒด ๊ณต๊ฐ„์„ ๊ตฌํ˜„ํ•˜๊ธฐ ์œ„ํ•œ ๊ธฐ์ €ํ•จ์ˆ˜(Base funtions)๋„ ์„œ๋กœ ์ƒ์ดํ•˜๋‹ค. ์ด์™€ ๊ฐ™์€ ์ฐจ์ด๋ฅผ ์ œ๊ฑฐํ•˜์—ฌ ๋‹จ์ผ ๊ฐ์ฒด๋ฅผ ๋„๋ฉด๊ณผ ํ•ด์„์— ๊ณตํ†ต์ ์œผ๋กœ ์‚ฌ์šฉํ•˜๊ธฐ ์œ„ํ•ด ๋‹จ์ผ๊ธฐํ•˜ ์œ ํ•œ์š”์†Œ๋ฒ• (Isogeometric finite element methods) ์„ ๊ฐœ๋ฐœํ•˜๋Š” ์—ฐ๊ตฌ๊ฐ€ ์ตœ๊ทผ ์ˆ˜ํ–‰๋œ ๋ฐ”๊ฐ€ ์žˆ๋‹ค(Hughes et al., 2005). ์ด ๊ธฐ๋ฒ•์—์„œ๋Š” ๋งˆ์น˜ ์บ๋“œํ™˜๊ฒฝ๊ณผ ๊ฐ™์€ ๋งค๋„๋Ÿฌ์šด ๊ณก๋ฉด์„ ๊ตฌํ˜„ํ•  ์ˆ˜ ์žˆ๋Š” NURBS (Non-uniform rational B-spline) ํ•จ์ˆ˜๋ฅผ ์œ ํ•œ์š”์†Œ ํ•ด์„์—์„œ๋„ ์ฑ„ํƒํ•˜์—ฌ ์—ฐ์†์ ์ธ ์‘๋ ฅ๋ถ„ํฌ๋ฅผ ์œ ํ•œ์š”์†Œ ๋ชจ๋ธ์—์„œ๋„ ๊ตฌํ˜„ํ•˜์˜€๋‹ค. ํ•˜์ง€๋งŒ, ๋‹จ์ผ๊ธฐํ•˜ ์œ ํ•œ์š”์†Œ๋ฒ•์˜ ๋ณด๊ฐ„ํ•จ์ˆ˜๋Š” ๋„ˆ๋ฌด ๋ณต์žกํ•˜์—ฌ ์œ ํ•œ์š”์†Œ ํ•ด์„ ํ”„๋กœ๊ทธ๋žจ์— ์ „๋ฐ˜์ ์œผ๋กœ ์ ์šฉํ•˜์—ฌ ์‚ฌ์šฉํ•˜๊ธฐ์—๋Š” ์•„์ง๋„ ์–ด๋ ค์›€์ด ์žˆ๋‹ค. ๊ทธ๋Ÿผ์—๋„ ๋ถˆ๊ตฌํ•˜๊ณ , ๋„๋ฉด ํ™˜๊ฒฝ๊ณผ ํ•ด์„ ํ™˜๊ฒฝ์„ ์ผ์น˜์‹œํ‚ค๋Š” ๊ฒƒ์— ๋Œ€ํ•œ ํ•„์š”์„ฑ์€ ๋„๋ฆฌ ์ธ์ •๋˜๊ณ  ์˜๋ฌธ์˜ ์—ฌ์ง€๊ฐ€ ์—†๋Š” ์ƒํ™ฉ์ด๋‹ค. ์ตœ๊ทผ ๊ฐœ๋ฐœ๋˜๊ณ  ์žˆ๋Š” BIM ํ™˜๊ฒฝ๋„ ์œ ํ•œ์š”์†Œ ํ•ด์„ ํ”„๋กœ๊ทธ๋žจ๊ณผ ์ง์ ‘ ์—ฐ๋™์ด ๊ฐ€๋Šฅํ•˜๋„๋ก ๊ฐœ๋ฐœ๋˜๊ณ  ์žˆ๋‹ค.

4.2 X-WIND ์†Œํ”„ํŠธ์›จ์–ด

4.2.1 ํ•ด์„ ํ™˜๊ฒฝ์˜ ๊ตฌ์„ฑ

๋„๋ฉดํ™˜๊ฒฝ๊ณผ ํ•ด์„ํ™˜๊ฒฝ์„ ์ผ์น˜์‹œํ‚ค๊ธฐ ์œ„ํ•ด, AutoCAD ๋„๋ฉด ํ™˜๊ฒฝ์—์„œ ํ•ด์„ ์ˆ˜ํ–‰์ด ๊ฐ€๋Šฅํ•œ X-WIND ํ”„๋กœ๊ทธ๋žจ์„ ๊ฐœ๋ฐœํ•˜์˜€๋‹ค.์ด๋•Œ ์ „์ฒ˜๋ฆฌ ๊ณผ์ •์—์„œ ์š”์†Œ๋ง ์ƒ์„ฑ์‹œ์—๋Š” AutoCAD์—์„œ ์ƒ์„ฑ๋œ ํ˜•์ƒ์„ ์ž๋™์œผ๋กœ GMSHํ”„๋กœ๊ทธ๋žจ๊ณผ ์—ฐ๊ฒฐํ•˜์—ฌ ํ•ด๋‹น ํ˜•์ƒ์— ์š”์†Œ๋ง์„ ๊ตฌ์„ฑํ•œ๋‹ค. ๋˜ํ•œ, ํ›„์ฒ˜๋ฆฌ ๊ณผ์ • ๋ฐ 2์ฐจ ๋ถ„์„๋„ AutoCAD ๋‚ด๋ถ€์—์„œ ์ง„ํ–‰๋œ๋‹ค. X-WIND์˜ ํ•ด์„ ์ ˆ์ฐจ๋ฅผ Fig. 9์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

4.2.2 ์ „ํ›„์ฒ˜๋ฆฌ๊ธฐ

AutoCAD์— ์œ ํ•œ์š”์†Œ ์—”์ง„์„ ์‚ฝ์ž…ํ•จ์œผ๋กœ์จ ์„ค๊ณ„ ์ž‘์—…์„ ํฌํ•จํ•œ ์ „ํ›„์ฒ˜๋ฆฌ๊ณผ์ •์„ AutoCAD์˜ ๊ทธ๋ž˜ํ”ฝ ๊ธฐ๋Šฅ์„ ์ด์šฉํ•ด์„œ ๊ตฌํ˜„ํ•˜์˜€๋‹ค. ์„ค๊ณ„์ž‘์—… ์ดํ›„, X-WIND๋Š” GMSH์„ ์‚ฌ์šฉํ•˜์—ฌ AutoCAD์—์„œ ๋ถˆ๋Ÿฌ์˜จ ํ˜•์ƒ์— ์š”์†Œ๋ง์„ ์ƒ์„ฑํ•œ๋‹ค. GMSH๋Š” 1998๋…„ ๊ฐœ๋ฐœ๋œ ์˜คํ”ˆ์†Œ์Šค ์š”์†Œ๋ง ์ƒ์„ฑ ํ”„๋กœ๊ทธ๋žจ์ด๋‹ค. AutoCAD์˜ ํ˜•์ƒ์€ OpenCASCADE ์ปค๋„์„ ํ†ตํ•ด ์š”์†Œ๋ง์„ ๊ตฌํ˜„ํ•˜๊ธฐ ์œ„ํ•ด iges ํŒŒ์ผ ํ˜•์‹์œผ๋กœ GMSH๋กœ ์ „์†ก๋œ๋‹ค. ์ƒ์„ฑ๋œ ์š”์†Œ๋ง์€ ๋‹ค์‹œ ๊ตฌ์กฐํ•ด์„ ์ž‘์—…์— ์‚ฌ์šฉ๋œ๋‹ค.

ํŒŒ๋ ฅ, ๋ฐ”๋žŒ, ๋ถ€๋ ฅ, ์ž์ค‘ ๋“ฑ์˜ ํ•˜์ค‘์ด ๋™์‹œ์— ์ž‘์šฉํ•˜๋Š” ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ๋ฌผ์˜ ํ•ด์„์„ ์œ„ํ•ด์„œ๋Š” ์ด๋“ค์˜ ํ•˜์ค‘์„ ๋ชจ๋‘ ๊ณ ๋ คํ•˜๋Š” ๊ฒƒ์ด ํ•„์ˆ˜์ ์ด๋‹ค. X-WIND์˜ ํ›„์ฒ˜๋ฆฌ๊ธฐ๋Š” ๊ตฌ์กฐ๋ฌผ์ด ๋ฐ›๋Š” ํ•˜์ค‘๋“ค์— ๋Œ€ํ•œ ํ•˜์ค‘์กฐํ•ฉ์„ ์ œ๊ณตํ•œ๋‹ค. ๊ฐ๊ฐ์˜ ํ•˜์ค‘์— ๋Œ€ํ•œ ํ•˜์ค‘๊ณ„์ˆ˜๋ฅผ ์‚ฌ์šฉ์ž๊ฐ€ ์ง์ ‘ ์„ ํƒํ•  ์ˆ˜ ์žˆ์œผ๋ฉฐ, X-WIND๋Š” ํ•˜์ค‘์กฐํ•ฉ์— ๋Œ€ํ•œ ๊ทธ๋ž˜ํ”„๋ฅผ ์ถœ๋ ฅํ•˜๋Š” ๊ธฐ๋Šฅ์„ ๊ฐ–์ถ”๊ณ  ์žˆ๋‹ค. ์ •์  ํ•˜์ค‘์€ ๊ตฌ์กฐ๋ฌผ์— ์••์ถ• ๋˜๋Š” ์ธ์žฅ ํŒŒ๊ดด๋ฅผ ์ผ์œผํ‚ค๋ฉฐ, ๋™์ ํ•˜์ค‘์€ ๋Œ€๊ฐœ ๊ฐ•๊ตฌ์กฐ๋กœ ์„ค๊ณ„๋˜์–ด ๋งŽ์€ ์šฉ์ ‘๋ถ€์œ„๋ฅผ ๊ฐ€์ง€๊ณ  ์žˆ๋Š” ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ๋ฌผ์— ํ”ผ๋กœ ํŒŒ๊ดด๋ฅผ ๋ฐœ์ƒ์‹œํ‚ค๊ธฐ ๋•Œ๋ฌธ์— ์ •์ ํ•˜์ค‘๊ณผ ๋™์ ํ•˜์ค‘์€ ์„ค๊ณ„์˜ ์ค‘์š”ํ•œ ๋ถ€๋ถ„์„ ์ฐจ์ง€ํ•œ๋‹ค. ๋”ฐ๋ผ์„œ, Fig. 10๊ณผ ๊ฐ™์ด ํ•˜์ค‘์กฐํ•ฉ์— ๋Œ€ํ•œ ๊ทนํ•œํ•œ๊ณ„์ƒํƒœ(ULS)์™€ ํ”ผ๋กœํ•œ๊ณ„์ƒํƒœ(FLS)๋ฅผ ๊ณ„์‚ฐํ•˜์—ฌ, ๊ฒ€ํ† ๋ฅผ ์ˆ˜ํ–‰ํ•  ์ˆ˜ ์žˆ๋Š” ๊ธฐ๋Šฅ์„ ์ถ”๊ฐ€ํ•˜์˜€๋‹ค. ULS์—์„œ๋Š” ๊ฐ๊ฐ์˜ ํ•˜์ค‘ ์กฐํ•ฉ์— ๋Œ€ํ•œ unity check๋ฅผ ์ˆ˜ํ–‰ํ•˜๊ณ  ๊ทธ ๊ฒฐ๊ณผ๋ฅผ ๊ทธ๋ž˜ํ”ฝ์œผ๋กœ ์ถœ๋ ฅํ•˜์—ฌ ์ œ์‹œํ•˜๋ฉฐ, FLS๋Š” ์‹œ๊ฐ„์˜์—ญ์—์„œ์™€ ์ฃผํŒŒ์ˆ˜ ์˜์—ญ์—์„œ์˜ ๋™์  ํ”ผ๋กœํ•ด์„์„ ์ˆ˜ํ–‰ํ•˜์—ฌ, ํ”ผ๋กœ ์†์ƒ์ •๋„๋ฅผ ๊ตฌํ•  ์ˆ˜ ์žˆ๋‹ค(Zi and Kim, 2020).

Fig. 10 ULS/FLS provided in X-WIND
../../Resources/ksm/jksmi.2023.27.4.33/fig10.png

4.2.3 ํ•ด์„๋ชจ๋“ˆ

X-WIND๋Š” X-SEA, X-OpenFAST, X-Nemoh์˜ 3๊ฐ€์ง€ ๋ชจ๋“ˆ์„ ์ด์šฉํ•ด ๊ตฌ์กฐํ•ด์„์„ ์ง„ํ–‰ํ•œ๋‹ค. X-OpenFAST์—์„œ ๊ณ„์‚ฐ๋œ ๊ณต๋ ฅ๊ณผ X-Nemoh์—์„œ ๊ณ„์‚ฐ๋œ ํ•ด์–‘ํ•˜์ค‘์€ X-SEA๋กœ ์ „๋‹ฌ๋˜์–ด ๊ตฌ์กฐํ•ด์„์ด ์ง„ํ–‰๋œ๋‹ค.

(1) ์ž…๋ ฅ ๋ชจ๋“ˆ๊ณผ ๋ฐ์ดํ„ฐ ์ €์žฅ

X-WIND๋Š” ์ž…๋ ฅํŒŒ์ผ๋กœ JSON (JavaScript Object Notation) ํŒŒ์ผ์„ ์‚ฌ์šฉํ•œ๋‹ค. ํ”Œ๋žซํผ๊ฐ„ ๋ฐ์ดํ„ฐ ์ „๋‹ฌ์„ ์ˆ˜ํ–‰ํ•˜๋Š” ํŒŒ์ผ ํ˜•์‹์€ ๋Œ€ํ‘œ์ ์œผ๋กœ XML๊ณผ JSON์ด ์žˆ๋‹ค. ๋‘ ์–ธ์–ด ๋ชจ๋‘ ํ…์ŠคํŠธ ๊ธฐ๋ฐ˜์œผ๋กœ ๋ฐ์ดํ„ฐ๋ฅผ ์ €์žฅํ•˜๊ณ  ์ „์†กํ•œ๋‹ค๋Š” ์ ์—์„œ ์ž…๋ ฅํŒŒ์ผ๋กœ ์‚ฌ์šฉํ•˜๊ธฐ ์ ํ•ฉํ•˜๋‹ค. ์ด์ค‘ XMLํŒŒ์ผ๋ณด๋‹ค ์ฒ˜๋ฆฌ์†๋„๊ฐ€ ์ˆ˜์‹ญ ๋ฐฐ ๋น ๋ฅด๊ณ  ์ปดํ“จํ„ฐ ๋ฆฌ์†Œ์Šค๋ฅผ 3๋ฐฐ ์ •๋„ ๋” ์ ๊ฒŒ ์‚ฌ์šฉํ•œ๋Š” JSONํŒŒ์ผ ํ˜•์‹์„ ์ž…๋ ฅํŒŒ์ผ๋กœ ์‚ฌ์šฉํ•˜์˜€๋‹ค(Nurseitov et al., 2009).

(2) X-SEA: ๊ตฌ์กฐํ•ด์„๋ชจ๋“ˆ

X-SEA๋Š” ๊ตฌ์กฐํ•ด์„ ๋ชจ๋“ˆ๋กœ์จ๊ณ„๋ฅ˜์„ ์„ ํฌํ•จํ•œ ๊ฐ์ข… ํ•ด์–‘ ๊ตฌ์กฐ๋ฌผ์˜ ์ •์  ํ•ด์„๊ณผ ๋น„์„ ํ˜• ๋™์  ํ•ด์„์„ ์ˆ˜ํ–‰ํ•œ๋‹ค. ๋ฌผ์„ฑ์น˜์™€ ๊ตฌ์กฐ๋ฌผ์˜ ํ˜•์ƒ์œผ๋กœ๋ถ€ํ„ฐ ์งˆ๋Ÿ‰๊ณผ ๊ฐ•์„ฑ์„ ๊ตฌํ•  ์ˆ˜ ์žˆ๊ณ  ํ•ด์–‘ํ•˜์ค‘, ๊ณต๋ ฅํ•˜์ค‘, ๊ณ„๋ฅ˜์„ ์œผ๋กœ๋ถ€ํ„ฐ ์˜ค๋Š” ํ•˜์ค‘์„ ํฌํ•จํ•œ ์™ธ๋ถ€ํ•˜์ค‘์„ ์ž…๋ ฅํ•˜์—ฌ ํ•ด์„์„ ์ง„ํ–‰ํ•œ๋‹ค. Table 2๋Š” X-SEA ๋ชจ๋“ˆ์—์„œ ์ˆ˜ํ–‰๊ฐ€๋Šฅํ•œ ๊ตฌ์กฐํ•ด์„์ข…๋ฅ˜๋ฅผ ๋‚˜ํƒ€๋‚ธ๋‹ค(Zi and Kim, 2020) .

Table 2 Solution features of X-SEA

Static analysis

Nonlinear static analysis

Linear dynamic analysis (Time integration method, mode superposition method, frequency domain)

Nonlinear dynamic analysis

Large deformation elastoplastic analysis (frame, shell and solid element)

Earthquake analyss (Response spectrum, Pushover analysis)

Environmental load (wave, current, Marine Growth, self-weight) and general load

Regular wave (Airy, Stokes, Cnoidal, Solitary, Stream function) and irregular wave(PM, JHONSWAP, Random)

3D Morrison and Diffraction pressure (Shell and solidelement)

Prestressing loss of tendon in PS concre

Joint Model: Rigid Offset, Local joint, Flexibility

Automatic calculation of Stress Concentration Factor (SCF)

Fatigue analysis (time and frequency domain)

Moooring line analysis of fixed and floating structucture

Pile-soil interaction analysis(p-y,t-z,Q-z), Pile superelement

Impact dynamic analysis in steel and concrete structures

Coupled dynamics analysis of OpenFAST and X-SEA

(3) X-OpenFAST: ๊ณต๋ ฅ ๊ณ„์‚ฐ ๋ชจ๋“ˆ

๋ฏธ๊ตญ NREL์˜ OpenFAST๋Š” ์œก์ƒ ๋ฐ ๊ณ ์ •์‹/๋ถ€์œ ์‹ ํ•ด์ƒ ํ’๋ ฅ ํ„ฐ๋นˆ์˜ ํ’๋ ฅ ํ„ฐ๋นˆ ์„ฑ๋Šฅ ๋ฐ ํ•˜์ค‘ ๊ณ„์‚ฐ์„ ์œ„ํ•œ ํ†ตํ•ฉ ์†Œํ”„ํŠธ์›จ์–ด ํŒจํ‚ค์ง€์ด๋‹ค. X-OpenFAST๋Š” OpenFAST ์ฝ”๋“œ๋ฅผ ๋ชจ๋“ˆํ™” ํ•œ ๊ฒƒ์œผ๋กœ, ์ „ํ›„์ฒ˜๋ฆฌ๊ธฐ๊ฐ€ ์—†๋Š” OpenFAST ์ฝ”๋“œ๋ฅผ ์ „ํ›„์ฒ˜๋ฆฌ๊ธฐ๋ฅผ ๊ฐ–์ถ”๊ณ  ์žˆ๋Š” X-WIND์— ์‚ฝ์ž…ํ•˜์—ฌ ์‚ฌ์šฉ์„ฑ์„ ์ฆ๊ฐ€์‹œ์ผฐ๋‹ค. X-OpenFAST์˜ Aerodyn์„ ์‚ฌ์šฉํ•˜์—ฌ, ๋ฐ”๋žŒ ๋ฐ ๋Œ€๊ธฐ์˜ ํ™˜๊ฒฝ์กฐ๊ฑด๊ณผ ์—์–ดํฌ์ผ ์ •๋ณด ๋ฐ ๋กœํ„ฐ์™€ ๋ธ”๋ ˆ์ด๋“œ ๋ฌผ์„ฑ์น˜๋ฅผ ์ž…๋ ฅํ•˜์—ฌ ํƒ€์›Œ์˜ ํ•˜๋‹จ๋ถ€์—์„œ ๋ชจ๋ฉ˜ํŠธ๋ฅผ ํฌํ•จํ•œ ํ•˜์ค‘์„ ์ถœ๋ ฅํ•œ๋‹ค. ์‚ฌ์šฉ์ž๋Š” ์ถœ๋ ฅํ•œ ๋ฐ์ดํ„ฐ๋ฅผ X-SEA์— ์ง์ ‘ ์ž…๋ ฅํ•˜์—ฌ ๊ตฌ์กฐํ•ด์„์„ ์ง„ํ–‰ํ•œ๋‹ค. ๋˜ํ•œ, X-WIND๋Š” X-OpenFAST๋ฅผ ํ†ตํ•ด ํ’๋ ฅ ํ„ฐ๋นˆ-ํƒ€์›Œ-ํ•˜๋ถ€ ๊ตฌ์กฐ๋ฌผ์— ๋Œ€ํ•œ ์™„์ „ ์—ฐ์„ฑํ•ด์„์„ ์ˆ˜ํ–‰ํ•  ์ˆ˜ ์žˆ๋‹ค.

(4) X-NEMOH: ํ•ด์–‘๋ ฅ ๊ณ„์‚ฐ ๋ชจ๋“ˆ

์„ธ์žฅํ•œ ๋ถ€์žฌ๋กœ ์ด๋ฃจ์–ด์ ธ ์žˆ๋Š” ๊ณ ์ •์‹ ํ•ด์–‘ ๊ตฌ์กฐ๋ฌผ์€ ๋ชจ๋ฆฌ์Šจ ๋ฐฉ์ •์‹์œผ๋กœ ํ•ด์–‘ํ•˜์ค‘์„ ๋ถ„ํฌํ•˜์ค‘์œผ๋กœ ์‚ฌ์šฉํ•œ๋‹ค. ๋ฐ˜๋ฉด, ์„ธ์žฅํ•œ ๋ถ€์žฌ๊ฐ€ ๊ฑฐ์˜ ์—†๋Š” ๋ถ€์œ ์‹ ๊ตฌ์กฐ๋ฌผ์€ ๋ชจ๋ฆฌ์Šจ ๋ฐฉ์ •์‹ ๋Œ€์‹  ํฌํ…์…œ ์ด๋ก ์„ ์‚ฌ์šฉํ•œ๋‹ค. X-NEMOH๋Š” ํฌํ…์…œ ์ด๋ก ์„ ๋ฐ”ํƒ•์œผ๋กœ ํ•ด์–‘ํ•˜์ค‘ ์••๋ ฅ์„ ๊ตฌํ•œ๋‹ค. ์••๋ ฅ์„ X-SEA์— ์ž…๋ ฅํ•˜๋ฉด X-SEA์—์„œ ๊ตฌ์กฐํ•ด์„์„ ์ง„ํ–‰ํ•œ๋‹ค.

(5) X-WIND ํ•ด์„ ์ ˆ์ฐจ

X-WIND๋Š” Fig. 11๊ณผ ๊ฐ™์ด ์œ„ ๋ชจ๋“ˆ๋“ค์„ ์ด์šฉํ•˜์—ฌ ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ๊ณผ ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ์— ๋Œ€ํ•œ ํ•ด์„์„ ์ง„ํ–‰ํ•œ๋‹ค.

๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ์˜ ๊ฒฝ์šฐ (1) X-OpenFAST์€ ํ„ฐ๋นˆ, ๋ธ”๋ ˆ์ด๋“œ, ํƒ€์›Œ์— ๋Œ€ํ•œ ํ•ด์„ ์ˆ˜ํ–‰ ํ›„ ์–ป์–ด์ง€๋Š” ํƒ€์›Œ ํ•˜๋‹จ๋ถ€์—์„œ์˜ ํž˜๊ณผ ๋ชจ๋ฉ˜ํŠธ ์ •๋ณด๋ฅผ X-SEA์— ์ „๋‹ฌํ•œ๋‹ค. (2) ์ด๋ฅผ ์ด์šฉํ•˜์—ฌ X-SEA๋Š” ํ•ด์„์„ ์ˆ˜ํ–‰ํ•œ๋‹ค.

๋ถ€์œ ์‹ ๊ตฌ์กฐ๋ฌผ์˜ ๊ฒฝ์šฐ (1) X-NEMOH์—์„œ ์œ ์ฒด ์ •์—ญํ•™์  ๊ฐ•์„ฑ(hydrostatic stiffness), ๋ถ€๊ฐ€์งˆ๋Ÿ‰(added mass), ๋ถ€๊ฐ€๊ฐ์‡„๊ณ„์ˆ˜(added damping coefficient), ๊ฐ€์ง„๋ ฅ(excitiation force) ๊ฐ’์„ X-OpenFAST์— ์ „๋‹ฌํ•œ๋‹ค. (2) X-OpenFAST๊ฐ€ ํ„ฐ๋นˆ, ๋ธ”๋ ˆ์ด๋“œ, ํƒ€์›Œ์— ๋Œ€ํ•œ ํ•ด์„ ํ›„ ์–ป์–ด์ง€๋Š” ํƒ€์›Œ์˜ ํ•˜๋‹จ๋ถ€์—์„œ ํž˜๊ณผ ๋ชจ๋ฉ˜ํŠธ ์ •๋ณด๋ฅผ X-Nemoh์— ์ „๋‹ฌํ•œ๋‹ค. (3) X-Nemoh๋Š” ๋‹ค์‹œ X-SEA์—๊ฒŒ ํ•ด์–‘ํ•˜์ค‘ ์••๋ ฅ๊ฐ’์„ ์ œ๊ณตํ•œ๋‹ค. (4) X-SEA๋Š” ์œ„ ์ •๋ณด๋“ค์„ ์ˆ˜ํ•ฉํ•œ ๋’ค ํ•ด์„์„ ์ง„ํ–‰ํ•œ๋‹ค.

Fig. 11 Concept map of X-WIND
../../Resources/ksm/jksmi.2023.27.4.33/fig11.png

5. X-WIND ์†Œํ”„ํŠธ์›จ์–ด ๊ฒ€์ฆ ์‚ฌ๋ก€ ๋ถ„์„

5.1 ๊ณ ์ •์‹ ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ ํ•ด์„ ๊ฒฐ๊ณผ์˜ ๋น„๊ต

X-WIND์˜ ์ ์šฉ์„ฑ์„ ๊ฒ€์ฆํ•˜๊ธฐ ์œ„ํ•ด ํ•œ๊ตญ ์„œ๋‚จํ•ด๋ฅผ ํ™˜๊ฒฝ์กฐ๊ฑด์œผ๋กœ ์„ ์ •ํ•˜๊ณ  NREL (The National Renewable Energy Laboratory)์˜ 5MW๊ธ‰ OWT (Offshore Wind Turbine) ๋ชจ๋ธ์„ ์‚ฌ์šฉํ•˜์—ฌ X-WIND ํ”„๋กœ๊ทธ๋žจ์„ ํƒ€ ํ”„๋กœ๊ทธ๋žจ(OpenFAST)๊ณผ ๋น„๊ต, ๊ฒ€์ฆํ–ˆ๋‹ค.

ํ˜„์žฌ ์„œ๋‚จํ•ด์—์„œ๋Š” 400MW ๊ทœ๋ชจ์˜ ๋ฐœ์ „๋‹จ์ง€๊ฐ€ ์„ค์น˜ ๊ณต์‚ฌ ์ค‘์— ์žˆ๋‹ค. 2020๋…„ 1์›” ํ•ด์ƒ ํ…Œ์ŠคํŠธ ๋ฒ ๋“œ๋กœ ํ™œ์šฉ๋œ 3MW๊ธ‰ ํ„ฐ๋นˆ ํ•ด์ƒํ’๋ ฅ ๋ฐœ์ „๊ธฐ 20๋Œ€์˜ ์ด 60MW๊ธ‰ ์‹ค์ฆ๋‹จ์ง€ ์ค€๊ณต์„ ์‹œ์ž‘์œผ๋กœ ํ•œ๊ตญํ•ด์ƒํ’๋ ฅ(์ฃผ)๋Š” ์‹œ๋ฒ”๋‹จ์ง€, ํ™•์‚ฐ๋‹จ์ง€์˜ ์ด 3๋‹จ๊ณ„ ๋‹จ์ง€ ๊ตฌ์ถ•์„ ๊ณ„ํš์ค‘์ด๋ฉฐ, ์‹ค์ฆ๋‹จ์ง€์— 5MW๊ธ‰ ํ„ฐ๋นˆ ํ•ด์ƒํ’๋ ฅ ๊ตฌ์กฐ๋ฌผ 4๋Œ€๋ฅผ ์ฆ์ถ• ์˜ˆ์ •์ด๋‹ค(Seo et al., 2019).

๋ณธ ์—ฐ๊ตฌ๋Š” NREL์˜ 5MW๊ธ‰ OWT ๋ชจ๋ธ์„ ์„ ํƒํ–ˆ๋‹ค. NREL 5MW๊ธ‰ OWT ๋ชจ๋ธ์€ NREL์ด ๋ˆ„๊ตฌ๋‚˜ ํ†ต์ผ๋œ ๋ชจ๋ธ๋กœ ํ”„๋กœ๊ทธ๋žจ๋“ค์„ ๋น„๊ตํ•˜๊ฒŒ ํ•˜๊ธฐ ์œ„ํ•ด ๊ฐœ๋ฐœํ•œ ๊ฒƒ์œผ๋กœ ๊ฐ€์žฅ ๋ณดํŽธ์ ์ด๊ณ  ๊ณต์‹ ๋ ฅ์ด ๋†’์€ ๋ชจ๋ธ์ด๋‹ค. ์„œ๋‚จํ•ด์˜ ํ•ด์ƒ ํ’๋ ฅ๋ฐœ์ „๊ธฐ๋Š” 3MW์ด์ง€๋งŒ ๋ณธ ์—ฐ๊ตฌ๋Š” X-WIND ํ”„๋กœ๊ทธ๋žจ์˜ NREL์˜ OpenFAST ํ”„๋กœ๊ทธ๋žจ๊ณผ ๋น„๊ต ๊ฒ€์ฆํ•˜๊ธฐ ์œ„ํ•ด 5MW OWT ๋ชจ๋ธ์„ ์‚ฌ์šฉํ–ˆ๋‹ค. ๋‹ค์Œ์€ ํ•œ๊ตญ ์„œ๋‚จํ•ด ํ™˜๊ฒฝ์กฐ๊ฑด์„ Table 3์œผ๋กœ ์ •๋ฆฌํ•œ ๊ฒƒ์ด๋‹ค.

Fig. 12์™€ Fig. 13๋Š” Monopile์˜ ์ผ๋ฐ˜ ํ•˜์ค‘ ์กฐ๊ฑด(a)๊ณผ ๊ทนํ•œ ํ•˜์ค‘ ์กฐ๊ฑด(b)์—์„œ TP (Transition piece) ์—ฐ๊ฒฐ๋ถ€์˜ x๋ฐฉํ–ฅ ๋ณ€์œ„๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ทธ๋ž˜ํ”„์™€ ๋ณ€์œ„ํ˜•์ƒ์ด๋‹ค. TP ์—ฐ๊ฒฐ๋ถ€๋Š” Fig. 12์— ํ‘œ์‹œ๋œ ๋ฐ”์™€ ๊ฐ™์ด ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ๋ฌผ๊ณผ ํ•ด์ƒํ’๋ ฅ ํƒ€์›Œ๋ฅผ ์—ฐ๊ฒฐํ•˜๋Š” ๋ถ€์žฌ๋กœ ์ง€์ง€๊ตฌ์กฐ๋ฌผ๊ณผ ํƒ€์›Œ ์‚ฌ์ด์— ์„ค์น˜๋œ๋‹ค(Shim et al., 2019). OpenFAST์™€ X-WIND์—์„œ์˜ TP ์—ฐ๊ฒฐ๋ถ€์˜ x๋ฐฉํ–ฅ์˜ ๋ณ€์œ„์˜ ์ถ”์„ธ๋Š” ๋ชจ๋‘ ๋™์ผํ•˜๋‹ค. ์˜ค์ฐจ์œจ์€ ๊ฐ 4.29%, 2.18%๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

Fig. 14์™€ Fig. 15๋Š” Tripod์˜ ์ผ๋ฐ˜ ํ•˜์ค‘ ์กฐ๊ฑด(a)๊ณผ ๊ทนํ•œ ํ•˜์ค‘ ์กฐ๊ฑด(b)์—์„œ TP ์—ฐ๊ฒฐ๋ถ€์˜ x๋ฐฉํ–ฅ ๋ณ€์œ„๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ทธ๋ž˜ํ”„์™€ ๋ณ€์œ„ํ˜•์ƒ์ด๋‹ค. OpenFAST์™€ X-WIND์—์„œ์˜ x๋ฐฉํ–ฅ์˜ ๋ณ€์œ„ ์˜ค์ฐจ์œจ์€ 20.73%, 3.20%์ด๋ฉฐ, ๋ณ€์œ„์˜ ์ถ”์„ธ๊ฐ€ ๋™์ผํ•˜๋‹ค.

Fig. 16๊ณผ Fig. 17์€ Jacket์˜ ์ผ๋ฐ˜ ํ•˜์ค‘ ์กฐ๊ฑด(a)๊ณผ ๊ทนํ•œ ํ•˜์ค‘ ์กฐ๊ฑด(b)์—์„œ TP ์—ฐ๊ฒฐ๋ถ€์˜ x๋ฐฉํ–ฅ ๋ณ€์œ„๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ทธ๋ž˜ํ”„์™€ ๋ณ€์œ„ํ˜•์ƒ์ด๋‹ค. OpenFAST์™€ X-WIND์—์„œ์˜ x๋ฐฉํ–ฅ์˜ ๋ณ€์œ„์˜ ์ถ”์„ธ๋Š” ๋ชจ๋‘ ๋™์ผํ•˜๋‹ค. ๋ณ€์œ„ ์˜ค์ฐจ์œจ์€ ๊ฐ๊ฐ 6.33%, 5.20%๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

Tripod์™€ Jacket ๊ตฌ์กฐ๋ฌผ์€ Monopile์— ๋น„ํ•ด ๋” ํฐ ์˜ค์ฐจ์œจ์„ ๋ณด์—ฌ์ฃผ์—ˆ๋‹ค. Tripod์™€ Jacket ๊ตฌ์กฐ๋ฌผ์€ ๊ตฌ์„ฑํ•˜๋Š” ๋ถ€์žฌ์˜ ๊ฐœ์ˆ˜๊ฐ€ ๋งŽ๊ณ  ๋ณต์žกํ•œ ๊ตฌ์กฐ๋ฅผ ๊ฐ€์ง€๊ธฐ ๋•Œ๋ฌธ์ธ ๊ฒƒ์œผ๋กœ ๋ณด์ธ๋‹ค. ์„ธ ๊ตฌ์กฐ๋ฌผ ๋ชจ๋‘ ๊ทนํ•œ ํ•˜์ค‘ ์กฐ๊ฑด์—์„œ์˜ ์˜ค์ฐจ์œจ์ด ์ผ๋ฐ˜ ํ•˜์ค‘ ์กฐ๊ฑด์˜ ์˜ค์ฐจ์œจ์— ๋น„ํ•ด ์ž‘์€ ๊ฒƒ์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ๋‹ค. ๊ทนํ•œ ํ•˜์ค‘ ์กฐ๊ฑด๋ณด๋‹ค ์ผ๋ฐ˜ ํ•˜์ค‘ ์กฐ๊ฑด์—์„œ ๋ณ€์œ„๊ฐ’์ด ๋” ์ž‘๊ธฐ ๋•Œ๋ฌธ์— ์ƒ๋Œ€ ์˜ค์ฐจ ๊ฐ’์ด ์ปค์ง„ ๊ฒƒ์œผ๋กœ ๋ณด์ธ๋‹ค. X-WIND์™€ OpenFast์˜ ์ƒ์ดํ•œ ์ •๋ฐ€๋„๋„ ๊ฒฐ๊ณผ ๊ฐ’์˜ ์ฐจ์ด๋ฅผ ์œ ๋ฐœํ•œ ๊ฒƒ์œผ๋กœ ๋ณด์ธ๋‹ค. ์œ„ ์˜ˆ์ œ์—์„œ ์„ธ ๊ตฌ์กฐ๋ฌผ ๋ชจ๋‘ ๊ทนํ•œ ํ•˜์ค‘ ์กฐ๊ฑด์—์„œ x์ถ• ๋ฐฉํ–ฅ ๋ณ€์œ„์˜ ๊ฒฝํ–ฅ์„ฑ์ด ์ผ์น˜ํ•˜๊ณ  ๋น„๊ต์  ํฐ ๋ณ€์œ„๊ฐ’์„ ๋ณด์ด๋Š” ๊ทนํ•œ ํ•˜์ค‘ ์กฐ๊ฑด์—์„œ ์ž‘์€ ์˜ค์ฐจ์œจ์„ ๋ณด์ธ๋‹ค๋Š” ์ ์—์„œ X-WIND๋ฅผ ๊ฒ€์ฆํ•˜์˜€๋‹ค.

Fig. 12 Comparison between OpenFAST and X-Wind under normal condition in monopile structure
../../Resources/ksm/jksmi.2023.27.4.33/fig12.png
Fig. 13 Comparison between OpenFAST and X-Wind under extreme condition in monopile structure
../../Resources/ksm/jksmi.2023.27.4.33/fig13.png
Fig. 14 Comparison between OpenFAST and X-Wind under normal condition in tripod structure
../../Resources/ksm/jksmi.2023.27.4.33/fig14.png
Fig. 15 Comparison between OpenFAST and X-Wind under extreme condition in tripod structure
../../Resources/ksm/jksmi.2023.27.4.33/fig15.png
Fig. 16 Comparison between OpenFAST and X-Wind under normal condition in jacket structure
../../Resources/ksm/jksmi.2023.27.4.33/fig16.png
Fig. 17 Comparison between OpenFAST and X-Wind under extreme condition in jacket structure
../../Resources/ksm/jksmi.2023.27.4.33/fig17.png
Table 3 Korean southwestern sea environmental conditions

Condition

Value

Water

Design water depth

50m

Water density

1025kg/m3

Wind

Air density

1.225kg/m3

Wind speed (Normal condition)

6.90m/s

50-year reference wind speed

(Extreme condtion)

42.99m/s

Wave

Wave heigh (Normal condition)

3.69m

Peak spectral period (Normal condition)

7.86s

50-year extreme wave height

(Extreme condtion)

5.97m

50-year extreme peak spectral period

(Extreme condtion)

11.18m

Current

Subsurface current speed

1.04m/s

Surface current speed

0.35m/s

5.2 ๋ถ€์œ ์‹ ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ ํ•ด์„ ๊ฒฐ๊ณผ์˜ ๋น„๊ต

๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ์˜ ๊ฒ€์ฆ์„ ์œ„ํ•ด Table 4์— ์ •๋ฆฌํ•œ ํ™˜๊ฒฝ์กฐ๊ฑด์„ NREL์˜ 5MW๊ธ‰ Spar ๋ชจ๋ธ์— ์ ์šฉํ•˜์˜€๋‹ค. ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ์€ ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ๊ณผ ๋‹ฌ๋ฆฌ ์ˆ˜์‹ฌ์ด ๊นŠ์€ ๊ณณ์— ์œ„์น˜ํ•˜๋ฏ€๋กœ ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ๋ฌผ๊ณผ ๋‹ค๋ฅธ ํ™˜๊ฒฝ ์กฐ๊ฑด์„ ์ ์šฉํ•˜์˜€๋‹ค. Fig. 18, Fig. 19์™€ Fig. 20์€ ์ฃผ์–ด์ง„ ํ™˜๊ฒฝ์กฐ๊ฑด์—์„œ X-WIND์˜ ํ•ด์„๊ฒฐ๊ณผ๋ฅผ OpenFAST์˜ ํ•ด์„๊ฒฐ๊ณผ์™€ ๋น„๊ตํ•œ ๊ทธ๋ž˜ํ”„์ด๋‹ค.

OpenFAST์™€ X-WIND์—์„œ์˜ x,y,z๋ฐฉํ–ฅ์˜ ๋ณ€์œ„์˜ ์ถ”์„ธ๋Š” ๋ชจ๋‘ ๋™์ผํ•˜๋‹ค. ๋ณ€์œ„ ์˜ค์ฐจ์œจ์€ ๊ฐ 4.146%, 18.64%, 27.67%๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. x์ถ•์— ๋น„ํ•ด y์ถ•, z์ถ• ๋ฐฉํ–ฅ ๋ณ€์œ„๊ฐ€ ์ž‘๊ธฐ ๋•Œ๋ฌธ์— ์ƒ๋Œ€์˜ค์ฐจ๊ฐ€ ์ปค์ง„ ๊ฒƒ์œผ๋กœ ๋ณด์ธ๋‹ค. ์„ธ ๋ฐฉํ–ฅ ๋ชจ๋‘ ์ถ”์„ธ๊ฐ€ ๋™์ผํ•˜๋‹ค๋Š” ์ ์—์„œ X-WIND๋ฅผ ๊ฒ€์ฆํ•˜์˜€๋‹ค.

Fig. 18 Comparison between OpenFAST and X-Wind of X-direction in spar structure
../../Resources/ksm/jksmi.2023.27.4.33/fig18.png
Fig. 19 Comparison between OpenFAST and X-Wind of Y-direction in spar structure
../../Resources/ksm/jksmi.2023.27.4.33/fig19.png
Fig. 20 Comparison between OpenFAST and X-Wind of Z-direction in spar structure
../../Resources/ksm/jksmi.2023.27.4.33/fig20.png
Table 4 Environmental conditions

Condition

Value

Water

Design water depth

320 m

Water density

1025 kg/m3

Wave height

6.00m

Wave period

10s

Airy wave

Air density

1.225 kg/m3

6. ๊ฒฐ ๋ก 

๋ณธ ๋…ผ๋ฌธ์€ ํ•ด์ƒํ’๋ ฅ ์ง€์ง€๊ตฌ์กฐ๋ฌผ์˜ ์„ค๊ณ„์™€ ํ•ด์„์„ ์ˆ˜ํ–‰ํ•  ์ˆ˜ ์žˆ๋Š” X-WIND ํ”„๋กœ๊ทธ๋žจ์„ ๊ตฌ์„ฑํ•˜์˜€๋‹ค. X-WIND๋Š” AutoCAD์— ์‚ฝ์ž…๋˜์–ด ๋‹จ์ผ ํ”Œ๋žซํผ์—์„œ ์„ค๊ณ„์™€ ํ•ด์„์„ ์ˆ˜ํ–‰ํ•จ์œผ๋กœ์„œ ๋ชจ๋ธ๋ง ์ž‘์—…์˜ ์ค‘๋ณต์„ฑ๊ณผ ์†Œํ”„ํŠธ์›จ์–ด๋“ค ๊ฐ„์˜ ๋ฐ์ดํ„ฐ ์ „๋‹ฌ ๊ณผ์ •์„ ์ƒ๋žตํ•  ์ˆ˜ ์žˆ์–ด ํ™œ์šฉ์„ฑ์ด ๋†’์„ ๊ฒƒ์œผ๋กœ ๊ธฐ๋Œ€๋œ๋‹ค. NREL 5MW๊ธ‰ OWT ๋ชจ๋ธ์„ ์‚ฌ์šฉํ•˜์—ฌ X-WINDํ”„๋กœ๊ทธ๋žจ์„ OpenFASTํ”„๋กœ๊ทธ๋žจ๊ณผ ๋น„๊ต ๊ฒ€์ฆํ•˜์˜€๋‹ค. ๊ฒ€์ฆ์„ ์œ„ํ•ด Monopile, Tripod, Jacket์˜ ๊ณ ์ •์‹ ์ง€์ง€๊ตฌ์กฐ ํ˜•์‹๊ณผ Spar์˜ ๋ถ€์œ ์‹ ์ง€์ง€๊ตฌ์กฐ ํ˜•์‹์„ ์ฃผ์–ด์ง„ ํ•˜์ค‘ ์กฐ๊ฑด์—์„œ ํ•ด์„ํ•˜์˜€๋‹ค. ํ•ด์„ ๊ฒฐ๊ณผ X-WIND์™€ OpenFAST๋Š” ์˜ค์ฐจ์œจ 27.67%์ด๋‚ด์˜ ๋ณ€์œ„๊ฐ’์„ ์ถœ๋ ฅํ•˜์˜€๊ณ  ๊ฒฝํ–ฅ์„ฑ์ด ์ผ์น˜ํ•˜๋Š” ๊ฒƒ์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ๋‘ ํ”„๋กœ๊ทธ๋žจ ๊ฐ„ ์˜ค์ฐจ์œจ์€ ๋งŽ์€ ๋ถ€์žฌ์˜ ๊ฐœ์ˆ˜, ์ผ๋ฐ˜ ํ•˜์ค‘ ์กฐ๊ฑด ํ•˜์—์„œ TP์—ฐ๊ฒฐ๋ถ€์˜ ์ž‘์€ ๋ณ€์œ„๊ฐ’, ๋‘ ํ”„๋กœ๊ทธ๋žจ์˜ ์ƒ์ดํ•œ ์ •๋ฐ€๋„๋กœ ์ธํ•ด ๋ฐœ์ƒํ•œ ๊ฒƒ์œผ๋กœ ๋ณด์—ฌ์ง„๋‹ค.

๊ฐ์‚ฌ์˜ ๊ธ€

์ด ๋…ผ๋ฌธ์€ 2023๋…„๋„ ์ •๋ถ€(์‚ฐ์—…ํ†ต์ƒ์ž์›๋ถ€)์˜ ์žฌ์›์œผ๋กœ ํ•œ๊ตญ์—๋„ˆ์ง€๊ธฐ์ˆ ํ‰๊ฐ€์›์˜ ์ง€์›์„ ๋ฐ›์•„ ์ˆ˜ํ–‰๋œ ์—ฐ๊ตฌ์ž„(20213030020200, ํ•ด์ƒํ’๋ ฅ์‹œ์Šคํ…œ ํ†ตํ•ฉํ•˜์ค‘ํ•ด์„ ํ”„๋กœ๊ทธ๋žจ ๊ฐœ๋ฐœ).

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