Performance Comparison of Bow and Stern Rudder for High-Speed Supercavitating Vehicles

Chuang Huang,Jianjun Dang,Kan Qin,Daijin Li,Kai Luo

doi:10.1155/2020/8630842

Chuang Huang, Jianjun Dang + Show 3 more

Open Access

https://doi.org/10.1155/2020/8630842

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Abstract

To predict the hydrodynamic characteristics and supercavity shape of supercavitation flows, the numerical model including VOF, cavitation model, and turbulence models is presented and validated by a well-established empirical correlation. The numerical method is then employed to simulate the high-speed supercavitating vehicles with two different types of control surfaces: bow rudders and stern rudders. The hydrodynamic characteristics and influences on the supercavity are compared. By contrast with the stern rudder, the bow rudder with the same wetted area is capable of generating a larger control force and moment. Also, the bow rudder introduces a considerable deformation to the forepart of the supercavity, while the stern rudder provides a negligible influence on the supercavity before it. In addition, the bow rudder is fully wetted, and the lift force only changes with the rudder angle. However, the stern rudder is partly wetted; the lift force is not only determined by the rudder angle but also related to the actual wetted status.

Highlights

High-speed supercavitating vehicles (HSSVs) are surrounded by supercavities and receive a very small skin friction drag as flying in air [1]. erefore, the sailing drag of HSSVs is largely reduced
Since the focus of this paper is to investigate the hydrodynamic characteristics of the bow rudder (BR) and stern rudder (SR) in the supercavitation flow and the supercavity deformations induced by the BR and SR, for the BR model, the attack angle of the HSSV is set as zero. e afterbodies of the HSSV including the fore-conic section, cylindrical section, and nozzle are completely enveloped in the supercavity and resultantly provide no effect on the hydrodynamic characteristics of the BRs and the supercavity shape. us, the afterbodies are excluded in the BR model for simplification, and only the BRs and cone cavitator are modeled
BR Model. e vertical BR deflects from 0° to 12° with an interval of 1°, and the corresponding numerical calculations are carried out to achieve the hydrodynamic characteristics of the BR. e rudder angle is defined as positive when the rudder rotates around the pivot in clockwise direction and as negative if it turns reversely

Summary

Introduction

High-speed supercavitating vehicles (HSSVs) are surrounded by supercavities and receive a very small skin friction drag as flying in air [1]. erefore, the sailing drag of HSSVs is largely reduced. The hydrodynamic characteristics and control strategy of HSSVs are largely different from the conventional underwater vehicles because of the existence of the supercavity and need to be further investigated [5]. E rudders are very crucial for the control of HSSVs and are traditionally arranged at the tail, for example, the “Shkval” designed by Russia Based on this layout scheme, Li et al study the kinetic characteristics and the motion stability of the directed HSSV by the lake-bed experiment [20]. Some results about the wedge-shaped rudder operating in the supercavitation flow are obtained, most of the experiments are carried out in water tunnels and the operation conditions are far different from those of the actual HSSV.

Problem Description

Numerical Model

Validation

Results and Discussion

Section I Section II Reference model

Conclusions