| Title |
Space-Time Characteristics of the Wall Shear-Stress Fluctuations in a Low-Reynolds Number Axial Turbulent Boundary Layer |
| Keywords |
Turbulent boundary layer ; 난류경계층 ; Direct numerical simulation ; 직접수치해법 ; Convex curvature ; 횡방향 곡률 |
| Abstract |
Direct numerical simulation database of an axial turbulent boundary layer is used to compute frequency and wave number spectra of the wall shear-stress fluctuations in a low-Reynolds number axial turbulent boundary layer. One-dimensional and two-dimensional power spectra of flow variables are calculated and compared. At low wave numbers and frequencies, the power of streamwise shear stress is larger than that of spanwise shear stress, while the powers of both stresses are almost the same at high wave numbers and frequencies. The frequency/streamwise wave number spectra of the wall flow variables show that large-scale fluctuations to the rms value is largest for the streamwise shear stress, while that of small-scale fluctuations to the rms value is largest for pressure. In the two-point auto- correlations, negative correlation occurs in streamwise separations for pressure and spanwise shear stress, and in spanwise correlation for both shear stresses. |