Estimation of friction velocity from the wind-wave spectrum at extremely high wind speeds

7th International Symposium on Gas Transfer at Water Surfaces

Takagaki, N.^1 ; Komori, S.^1 ; Suzuki, N.^2

Department of Mechanical Engineering and Science, Advanced Research Institute of Fluid Science and Engineering, Kyoto University, Kyoto

615-8540, Japan^1

Department of Mechanical Engineering, Kinki University, Osaka

577-8502, Japan^2

关键词: Field measurement;    Friction velocity;    High wind speed;    Tropical cyclone;    Water-level fluctuation;    Wave measurement;    Wind wave spectrum;    Wind-wave tanks;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/35/1/012009/pdf
DOI  :  10.1088/1755-1315/35/1/012009

来源: IOP

【 摘 要 】

The equilibrium range of wind-waves at normal and extremely high wind speeds was investigated experimentally using a high-speed wind-wave tank together with field measurements at normal wind speeds. Water level fluctuations at normal and extremely high wind speeds were measured with resistance-type wave gauges, and the wind-wave spectrum and significant phase velocity were calculated. The equilibrium range constant was estimated from the wind-wave spectrum and showed the strong relationship with inverse wave age at normal and extremely high wind speeds. Using the strong relation between the equilibrium range constant and inverse wave age, a new method for estimating the wind speed at 10-m height (U10) and friction velocity (u∗) was proposed. The results suggest that U10and u∗ can be estimated from wave measurements alone at extremely high wind speeds in oceans under tropical cyclones.