Thermodynamic analysis and numerical modeling of hurricane intensity has shown that it is sensitive to enthalpy and momentum transfer from the ocean surface. Direct measurements of drag, evaporation, and sensible heat transfer are not easily performed on the high seas. Therefore, a wind wave tank has been constructed in which a few aspects of a tropical storm boundary layer are simulated. The air velocity inside the annular tank is comparable to that of a hurricane. However, the three dimensionality of the tank obscures the quantitative comparison between experiments and actual conditions over the surface of the ocean at high wind speeds.

The design of the wind wave tank and the initial experiments create a foundation for future and more comprehensive experimental programs. This talk focuses mainly on the design and engineering of the tank and the fluid mechanics of the rotational flow in the tank, using angular momentum analysis. It provides experimental data on drag at high wind speeds obtained using spindown experiments. A methodology for the measurement of the enthalpy transfer is outlined and numerical values for it in low wind speed are also provided. The effect of water spray in the tank on the drag and enthalpy transfer is discussed and compared to the possible effect of ocean spray at high wind speed.