The Vortex-Boundary Element Method - New pressure methods for application to the external flow noise problem

Three new methods to compute pressure within a vortex method are developed and presented. Although demonstrated in a Vortex-Boundary Element Method, these pressure methods are suitable for any vortex method. They have computational savings of 2-3 orders of magnitude over a standard Poisson pressure method when surface pressure at a small set of locations is desired. This savings is significant as the computational time needed to solve for the pressure field using a Poisson method exceeds that of the VBEM. for cases similar to those studied here.. These methods are validated for flow on the front face of a cube set orthogonal to a uniform freestream flow. Flow about a cube yawed at 30” to the streamwise direction is simulated. Timeaveraged ‘flow field data and surface pressure spectra are presented for Reynolds numbers of 500 and 1500. The results of the calculations correctly predict an overall sound pressure level increase with increasing Reynolds numbers. The VBEM also captures the different levels of pressure fluctuations associated with different flow regions. This work also serves as a successful first step in demonstrating the potential of the VBEM for use in computing unsteady flows to predict the pressure spectrum associated with the unsteady surface pressure fluctuations.