An integrated approach to the design of supercavitating underwater vehicles

Supercavitating underwater vehicles;Configurational optimization;Trim analysis;Dynamic simulation;Trajectory optimization of maneuvering vehicles;Flight dynamics;Underwater vehicle design

Ahn, Seong Sik ; Aerospace Engineering

University:Georgia Institute of Technology

Department:Aerospace Engineering

关键词: Supercavitating underwater vehicles;    Configurational optimization;    Trim analysis;    Dynamic simulation;    Trajectory optimization of maneuvering vehicles;    Flight dynamics;    Underwater vehicle design;   

Others  :  https://smartech.gatech.edu/bitstream/1853/16237/1/ahn_seong_s_200708_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

A supercavitating vehicle, a next-generation underwater vehiclecapable of changing the paradigm of modern marine warfare, exploitssupercavitation as a means to reduce drag and achieve extremely highsubmerged speeds. In supercavitating flows, a low-density gaseouscavity entirely envelops the vehicle and as a result the vehicle isin contact with liquid water only at its nose and partially over theafterbody. Hence, the vehicle experiences a substantially reducedskin drag and can achieve much higher speed than conventionalvehicles. The development of a controllable and maneuveringsupercavitating vehicle has been confronted with various challengingproblems such as the potential instability of the vehicle, theunsteady nature of cavity dynamics, the complex and non-linearnature of the interaction between vehicle and cavity. Furthermore,major questions still need to be resolved regarding the basicconfiguration of the vehicle itself, including its control surfaces,the control system, and the cavity dynamics. In order to answerthese fundamental questions, together with many similar ones, thisdissertation develops an integrated simulation-based design tool tooptimize the vehicle configuration subjected to operational designrequirements, while predicting the complex coupled behavior of thevehicle for each design configuration. Particularly, this researchattempts to include maneuvering flight as well as various operatingtrim conditions directly in the vehicle configurationaloptimization. This integrated approach provides significantimprovement in performance in the preliminary design phase andindicates that trade-offs between various performance indexes arerequired due to their conflicting requirements. This dissertationalso investigates trim conditions and dynamic characteristics ofsupercavitating vehicles through a full 6 DOF model. The influenceof operating conditions, and cavity models and their memory effectson trim is analyzed and discussed. Unique characteristics areidentified, e.g. the cavity memory effects introduce a favorablestabilizing effect by providing restoring fins and planing forces.Furthermore, this research investigates the flight envelope of asupercavitating vehicle, which is significantly different from thatof a conventional vehicle due to different hydrodynamic coefficientsas well as unique operational conditions.