Numerical and Experimental Study of Flow Field between the Main Hull and Demi-Hull of a Trimaran

Abstract

The interactions between the main hull and demi-hull of trimarans have been arousing increasing attention, and detailed circumferential flow fields greatly influence trimaran research. In this research, the unsteady wake flow field of a trimaran was obtained by Reynolds-Averaged Navier-Stokes (RANS) equations on the basis of the viscous flow principles with consideration of the heaving and pitching of the trimaran. Then, we designed an experimental method based on particle-image velocimetry (PIV) and obtained a detailed flow field between the main hull and demi-hull of the trimaran. A trimaran model with one demi-hull made of polycarbonate material with 90% light transmission rate and a refractive index 1.58 (close to that of water 1.33) was manufactured as the experiment sample. Using polycarbonate material, the laser-sheet light-source transmission and high-speed camera recording problems were effectively rectified. Moreover, a nonstandard calibration was added into the PIV flow field measurement system. Then, we established an inverse three-dimensional (3D) distortion coordinate system and obtained the corresponding coordinates by using optics calculations. Further, the PIV system spatial mapping was corrected, and the real flow field was obtained. The simulation results were highly consistent with the experimental data, which showed the methods established in this study provided a strong reference for obtaining the detailed flow field information between the main hull and demi-hull of trimarans.

Design Process and Advanced Manufacturing of an Aquatic Surface Vehicle Hull for the Integration of a Hydrogen Power Plant Propulsion System

“…The outrigger layout, which refers to the longitudinal and transverse distance between the main hull and the two outriggers, can be optimized to reduce the interference wave resistance between the main hull and the outriggers by means of both numerical [39] and experimental studies [41]. The results of Ghadimi et al [39] showed that trimaran vessels have suitable dynamics with lower longitudinal side bodies and large transversal distances, which was also confirmed by the work of Sun et al [52], in which the flow field between the main hull and demihull can be observed. Moreover, Khoob et al [41] concluded that symmetric side hull shapes had better performance in terms of total resistance than inboard or outboard shapes.…”

Dynamic analysis of shallow embedded jacket offshore structures under wave forces

“…Therefore, the numerical analysis of the impact of the seabed on wave force on the single pile and the results showed that the seabed attenuated wave propagation and increased wave force [13,15,18,19]. However, the above research does not involve the influence of the dynamic process, structural form, the buried depth, wave parameters and other factors on structural wave force [20][21][22] (Fig. 1).…”

CFD Analysis into the Resistance of Trimaran with Longitudinal Sidehull Adjustments

“…The location of the side hull has a profound effect on ship resistance, Poundra et al pointed out because it has a strong influence on both the longitudinal and transverse dynamics [11], Trimarans also experience this interference phenomenon to a greater degree. Flow field interaction between trimaran ships' hulls is shown by Sun et al [12] using numerical calculations and PIV experiments to show the flow field between the main hull and the side hull can be recorded with a high resolution in both microscopic and macroscopic structure. Residual resistance levels may be reduced by using the right trimaran arrangements [13], However, the previous study did not include the effects of side hull placement longitudinally, from stern to bow.…”