Optimization of the maximum range of supercavitating vehicles based on a genetic algorithm. (1st November 2021)

• Record Type: Journal Article
• Authors: Zou, Wang; Liu, Tingxu; Shi, Yongkang
• Is Part Of: Ocean engineering. Volume 239(2021)
• Publication Date: 2021-11-01
• Subjects: Supercavity -- Supercavitating vehicle -- Optimization model -- Genetic algorithm -- Range; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2021.109892
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: Range is an important indicator for measuring the performance of supercavitating vehicles (SCAVs), which is closely related to the hydrodynamic layout of vehicles. The motion state, cavitating flow and control surfaces of a vehicle, which are key factors that affect the hydrodynamic distribution, have an important impact on the range. A range optimization model is established for a SCAV on a straight and level trajectory, wherein the optimal variables include the cavitator number, speed of motion, diameter and deflection angle of the cavitator, pitch angle and fin deflection angle. The global search performance of the adaptive genetic algorithm is improved by segmenting the main optimization variables and performing multiple optimizations in each segment, thereby resulting in the development of a program called the genetic-ZouLiu code (GE-ZL Code). Based on the optimization model, some geometric characteristic and motion parameters of natural and ventilated SCAVs are optimized to the maximum ranges using the GE-ZL Code. Analyses are performed to determine the influences of the navigation depth and slenderness ratio of the vehicle on the optimization results, i.e., the change trends of the optimization variables and the maximum range with the change in the navigation depth and slenderness ratio. Additionally, the optimization results of the two vehicles are compared and analyzed. Furthermore, based on the optimization results, the relationships among the cavitator diameters, column body diameters and full lengths of the vehicles are formulated using the nonlinear least square method. Based on the analyses of the afterbody force characteristics, the study also shows that the SCAV can rely on only the deflections of the cavitator and fin to achieve good horizontal straight navigation without other wetted afterbodies by optimizing geometric characteristic and motion parameters. Highlights: The range optimization model is established for a SCAV in a horizontal trajectory. The adaptive genetic algorithm is improved to optimize natural and ventilated SCAVs. SCAV's geometric and motion parameters are optimized to reach the maximum range. Relationships among key geometric parameters of optimized SCAVs are formulated. SCAVs can rely on only control surfaces' deflections for horizontal straight motions.