Hypersonic pressure-controllable bump based on an improved permeable-boundary method

Abstract This paper presents a novel design method of pressure-controllable bump for hypersonic aircraft forebody. The new developed method can effectively resolve the tradeoff among boundary layer diversion, flow uniformity, and external drag reduction. The classical permeable-boundary method is improved by coupling with the radius-based function, through which the prescribed surface pressure distribution can inversely generate the bump. The improved permeable-boundary method is available for 3D unstructured mesh which increases the solution efficiency and robustness. The accuracy of the method is evaluated through the comparison with experimental results. In addition, five principles to arrange the pressure distribution are proposed. Then, a new pressure-controllable bump is designed. Compared with the typical streamline-tracing bump, the new bump is 44.9% lower in height while diverting identical low kinetic energy flow. According to the space occupied with high kinetic energy flow, the uniform region to preset the inlet of the new bump is 58.0% wider than that of the typical bump. Moreover, the usage efficiency of high kinetic energy flow is 1.5% higher. The new bump is less convex and its equivalent lift-to-drag ratio is two times greater than the typical bump. This research confirms that the new pressure-controllable bump shows better integrating capacity with the hypersonic inlets than the typical bump. The current design method is based on an inviscid condition; the method considering the viscous effects will be further studied in the future.