Features of Profiles for Currents, Momentum Flux, and a Turbulence Dissipation Rate in Wind-Wave Channel

Vertical profiles of the mean horizontal currents U ( z ), the vertical momentum fluxes τ( z ), and the turbulence kinetic-energy dissipation rates (TKE dissipation rate) ε( z ) in the upper water layer (UWL) are considered and their joint analysis is carried out. For this purpose, data from laboratory measurements performed in the wind-wave channel of the Institute of Applied Physics, Russian Academy of Sciences (RAS) [1, 2], are used. They correspond to conditions of strong wind and breaking wind waves. The profiles of the currents and momentum fluxes are estimated for x and z components of the velocity at five horizons in the UWL at four various wind values. The empirical estimates of ε( z ) obtained from the same data in the previous work [3] are used in the joint analysis. It is established that (a) velocity of currents U ( z ) increases noticeably when compared to the values of U ( z ) in the absence of waves, (b) the momentum flux in the water τ w ( z ) decreases noticeably when compared to that in the air τ a ( z ), and (c) τ w ( z ) significantly attenuates with depth according to ratio τ w ( z ) ~ 1/ z 2 . The mentioned anomalies of profiles U ( z ) and τ( z ) in the UWL are analyzed together with the previously determined pattern of TKE dissipation-rate falloff with depth according to ratio ε( z ) ~ 1/ z 2 in order to search for an interpretation of the results.