High-Speed Trimaran Drag: Numerical Analysis and Model Tests

Abstract

A numerical technique for high-speed trimaran resistance calculation is developed. The technique is based on the modified viscous-inviscid interaction concept and quasi-linear theory of wave resistance (Amromin et al 1984). The key element of this technique, which is called modified quasi-linear theory (MQLT), is an account of Froude number influence on the ship trim, transom drag, and wetted surface. This influence leads to appearance of a drag component that significantly depends on both Reynolds number and Froude number. This component has been traditionally included in residuary drag in the model test data. The presented preliminary numerical results were obtained with simplifications of the boundary layer theory that are acceptable for slender hulls. Calculated drag is in sufficient accordance with results of model tests. The MQLT computations of boundary layers are also compared with the Reynolds averaged Navier-Stokes (RANS) calculations(one-equation turbulence model by Spalart and Allmaras 1992) at model and ship scale Reynolds numbers. An analysis of the model-ship scale correlation factor for high-speed slender hulls with transom sterns and diverse mutual position of the trimaran hulls is done.

Preparation of Superhydrophobic Surfaces Based on Rod-Shaped Micro-Structure Induced by Nanosecond Laser

“…Underwater operation equipment, such as underwater robots, underwater unmanned vehicles, and towed sonar, would be subjected to great resistance in the process of navigation, resulting in a decrease in navigation efficiency and an increase in energy consumption. This is mainly attributed to the adhesion of water to the metal surface caused by the boundary layer effect [1,2]. According to previous research, the frictional resistance caused by water adhesion can account up to 80-85% of the total resistance [3].…”