Characterization of Onboard Wind by Comparing Two Anemometers

Characteristics of onboard wind measurements and hull effects were investigated by comparing the onboard wind on starboard and port sides of a ship. The wind directions and speeds measured by both anemometers were roughly in agreement on average. However, deviation often exceeded the of Ficial accuracy, and the trend on wind direction differed depending on the wind direction. The wind direction gap is large on the wind direction where only one anemometer is influenced by the structures. The wind direction gap is small on the wind direction where is no structures. The winds from −100~+ 100 are influenced by the main mast, and go around the aft side of the main mast. Wind from aft side is more likely to blow through on lee-side. Wind from fore-side is intercepted and reduced. The winds from between the bow <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim\pm 100^{\circ}$</tex> are influenced by the main mast, and go around aft side of the main mast. The winds from between stern <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim\pm 110^{\circ}$</tex> are influenced by the aft structures, and go around fore side of the structures. Wind from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 80^{\circ}\sim\pm 140^{\circ}$</tex> is more likely to blow through, so the wind speed is larger on the lee-side. The wind from the directions which are intercepted by the main must and the aft structures is reduced on the lee-side.