Identification Of The Propeller-Induced Pressure Fluctuations

Around the propeller and its wake of the deepening field of study, recognizing that the propeller unsteady pressure fluctuations generated excitation force and its axis is not enough to cause intense vibration of the ship stern, and the culprit is not the propeller uniform wake field generated in the work of the unsteady blade cavity and tends to cause drastic changes in the amplitude of the pulse with phase pressure, its value far exceeds the non-cavitating conditions, the propeller-induced pressure fluctuations.Currently has propeller the surface of the hull pressure fluctuations induced by the size of the propeller design as the success of a standard. Therefore, if a simple and accurate identification of the fluctuating pressure of the size of the propeller, the propeller research design and to avoid damaging the ship or a strong vibration are of great significance.Based on the frequency domain load identification method in the inverse frequency response function directly Identification of the principle of load, first with a finite element theory and boundary element method of combining the structure obtained with unilateral flooding frequency response function, the displacement transfer sensor measured the structural response of a number of points, and then use two-dimensional polynomial theory the two unknown dimensional distribution of dynamic load (pulse pressure) that the order for the linear superposition of orthogonal basis functions, then the unknown complex complex distributed dynamic load identification can fit into a simple orthogonal factor recognition.Measured as long as the structure points greater than the response coefficients to be identified, we can identify the coefficients,which can identify the pulse pressure to power purposes.The numerical simulation results show that the method can identify two-dimensional dynamic load distribution, to avoid the direct frequency response function then the matrix inverse ill-posed problem when the law can interfere with good noise suppression, while the method has good recognition accuracy and can combine with the finite element method to identify the distribution of complex structures on the dynamic load.The proposed identification method propeller fluctuating pressure fluctuating pressure for recognition of the real ship maneuverability and economy, but also has good engineering versatility.