Numerical and Experimental Evaluation of Waterjet Propelled Amphibious Tracked Vehicles

This paper covers the numerical and experimental evaluation including vehicle resistance and self-propulsion performance, waterjet flow rate, and running attitude changes of an amphibious tracked vehicle. A reduced-scale model of the waterjet propelled amphibious tracked vehicle was designed by the Agency for Defense Development (ADD) and was tested in the towing tank. The numerical study was performed over a speed range of 0.3<Froude number (Fn)<0.8 using a second order accurate finite volume method provided by a commercial computational fluid dynamics (CFD) tool to solve the governing Reynolds Averaged Navier-Stokes (RANS) equations. The k-ω model was used for the turbulence closure and the massive separation flow behind the box-shaped-vehicle. The rotation of the impeller was simulated by a moving reference frame method and the running attitude was predicted by a dynamic body fluid interaction method. Good agreement is found for the prediction of the resistance, thrust and torque coefficients of the impeller. The comparisons also made it possible to determine appropriate installation angles of the stern hydrofoil for achievement of lower shaft delivered power and more stable running attitude for high speed amphibious tracked vehicles.