A verification of two shear velocity equations for the wind-wave interaction in a lake environment

Under growing wind-wave conditions the shear velocity,u _*, over the water surface equalsg ² H _s ² B _a ² C _p ³ , whereg is the gravitational acceleration,H _s is the significant wave height,B _a is a constant, andC _p is the wave celerity. From an independent field experiment in a lake environment which provided all three parameters (u _*,H _s , andC _p ), the value ofB _a is found to be 0.89, which is slightly lower than but consistent (within 20%) with the literature value between 0.90 and 1.06 obtained from an oceanic environment. Since thisu _* equation does not include the wind speed,U ₁₀, anotheru _* formulation withU ₁₀ in addition to the wave information is also evaluated. It is shown that the latter equation which includesU ₁₀ is superior to the former withoutU ₁₀.