Airflow distortion at instrument sites on the RV Ronald H. Brown

Wind speed measurements obtained from research ships are prone to systematic errors caused by the distortion of the air flow around the ship’s hull and superstructure. In this report the air flow around the RV Ronald H. Brown is simulated at two relative wind directions using Computational Fluid Dynamics (CFD). The airflow distortion at three anemometer sites has been quantified for wind speed of 15 ms-1 blowing a) directly over the bows of the ship, and b) from 30º to port of the bow. All anemometers in this study were located in the bows of the ship and experienced moderate flow distortion, with the wind speed being decelerated by 1% to 4% depending on the instrument location and the wind direction. The flow had been displaced vertically by about 0.7 m for the bow-on flow and by about 0.9 m for the flow from 30º to port.