Measurement Investigation Of Complex Eddy Viscosity Model In Wavy Wall Turbulent Boundary Layer With PIV

In this dissertation, a technique termed 2D-TRPIV was utilized to measure the turbulent flows over a sinusoidal solid wavy boundary with a height to length ratio of 2a / ? ? 0.14in a water channel. A series of experiments were designed and implemented under three conditions where three kinds of Reynolds numbers were defined respectively, obtaining sets of 3000 instantaneous velocity fields. Thus the statistical quantities were calculated including the mean streamwise (U ) and normal (V ) velocities, the root-mean-square (rms) values of the streamwise, (u 2 )^1/2, and normal ( v 2 )1/2 turbulent velocity fluctuations and the mean Reynolds shear stress (- uv ). The statistical quantities mentioned above were measured in two kinds of Reynolds numbers. The distributions of the mean streamwise (U ) and normal (V ) velocities are regularly near the wavy boundary. The locations of the maximum of (u 2 )^1/2, ( v 2 )^1/2and (-uv ) are near the wavy wall, and all of them decreased in the outer region. The ejection events were found near the trough of the wavy wall.The phase difference between Reynolds-stress component and normal gradient of the longitudinal velocity, r₁₂- 12, and the phase difference between and longitudinal gradient of the longitudinal velocity, r₁₁- 11 were intensively studied by used of cross-correlation technique in three instance. In general, the - 12 and - 11 are found to be less than 180°near the wavy boundary. In outer region, the distribution of - 11 are more regular than the distribution of - 12.