Hydrodynamic modeling of LMRS unmanned underwater vehicle and tow tank test validation

A rapid engineering method using body build-up approach to predict nonlinear hydrodynamic forces and moments on the Long Term Mine Reconnaissance System (LMRS) autonomous, unmanned underwater vehicle (UUV) is presented. Semiempirical equations representing the hydrodynamic model for calculating loads on the UUV´s geometric components, such as bare body, control fins, recovery ring, and Thrust-Vectored Pumpjet (TVPJ) propulsor are described. Numerical results of the predicted total forces and moments on the vehicle are presented over a range of angle of attacks, vehicle speeds, control fin deflections, and propulsion ratios. The hydrodynamic performances of the vehicle were studied. The results indicated that the vehicle stability tends to decrease with increasing speed, and the control fin effectiveness decreases with decreasing speed and propulsion ratio. Excellent agreement was obtained between the predicted results and test data measured from full-scale model testing conduced at David Taylor Model Basin. The results of the study and tow tank test are described.