Sonic Boom propagation using high and low-fidelity methods

A bottle neck to the introduction of civil supersonic aircraft is represented by the noise produced by shock waves during the cruise flight, the so-called "sonic boom". Authorities prohibit supersonic flight over land due to the exceeding noise levels produced by sonic boom. This work deals with a comprehensive methodology for assessing the aircraft sonic-boom signature at ground level starting from an accurate estimation of the near-field pressure signature caused by shock-wave pressure. High fidelity computational fluid dynamics (CFD) is typically used to calculate near-field sonic booms, whereas proper models are used for propagating at long distances, since CFD becomes computationally demanding as propagation distances exceed 10 km. The present study focuses on assessing a low-fidelity technique (e.g. Whitam's equation) against the direct application of a high-fidelity CFD method for sonic boom propagation at a medium distance. The former propagates the pressure signature through an analytical formulation, exploiting the CFD sonic boom pressure data extracted at a shorter distance. This work shows how the low-fidelity technique guarantees outcomes with comparable levels of accuracy of the direct CFD but requiring less computing resources. A range of aircraft, including a hypersonic test bench and a configuration similar to the Concorde, were chosen as test cases within the framework of the European project MORE&LESS.