Dynamics and Control of Supercavitating Bodies

Analytical and numerical investigations conducted into the control of dive-plane dynamics of supercavitating bodies are presented. Particular attention is paid to tail-slap behavior. A fundamental understanding of the solution structure in terms of equilibrium and other solutions developed through the effort is discussed, and control schemes used to realize stable inner loop dynamics are presented. Dominant nonlinearities associated with planning forces are taken into account in the model and controllability of the system with the fin input and/or the cavitator input has been examined. The describing function method is brought to bear upon this problem and the presence of limit cycles in the controlled and uncontrolled cases are explored. The nonlinear planing force associated with tail-slap behavior is approximated as a piecewise linear function and the results obtained from switching feedback control analysis are provided.