Wind Tunnel Investigation into the Drag Characteristics of A Pair of Demihull Catamaran in Proximity

Abstract

An experimental investigation into drag characteristics of a pair of demihull catamaran was carried out using low-speed wind tunnel at Department of Mechanical Engineering, Sepuluh Nopember Institute of Technology (ITS), Surabaya. Full viscous drag investigations were performed without and with turbulence transition strip at the range of Reynolds numbers 2.9x105 – 4.5x105. The model hull forms comprise a twin model of hull similar to NPL 4a along which are separated laterally. The results obviously demonstrate the effect of hull separation. The experimental work shows that the pressure coefficient increases while the flow velocity decreases when the hull clearance was closer. Furthermore, viscous drag of model with turbulence strip was higher 1.8% than that of non turbulence strip. The experimental results are presented in tables and graphical forms and the drag characteristics and interference effects are discussed and compared with published data in which show good agreement.