In Silico Evaluation of Sonic Ring Standoff and Trailing Edge Expansion on Hypersonic Waverider Performance

Waveriders are a distinguished class of hypersonic vehicles, celebrated for their superior aerodynamic performance enabled by a shock-attached design. Their geometry is tailored to maintain an attached oblique shock along the lower surface, maximizing lift and maneuverability in high-speed flight regimes. However, this aerodynamic advantage comes with a critical thermal drawback. The attached shock induces intense entropy waves, primarily due to the reduced standoff distance of the sonic ring, which facilitates the development of a non-isentropic layer—commonly referred to as the Vinay layer. To address these competing effects, this study investigates the aerodynamic and thermal performance of waveriders at Mach 6 and 25 km altitude using validated numerical simulations. Previous research compared two nose configurations—one based on a classic Haack profile and another incorporating a rectangular cavity. The cavity design was found to increase the standoff distance of the sonic ring, reducing peak surface heat flux by promoting entropy wave dissipation and vortex generation, thereby enhancing thermal resilience. Additionally, configurations with blunt trailing edges demonstrated superior heat tolerance compared to sharp ones. Building on these insights, the current study evaluates a redesigned waverider with an integrated expansion region at the trailing edge. This modification aims to accelerate the aft flow, reduce upper-surface pressure, and enhance lift without relying on conventional wings, as waveriders depend solely on body shaping and propulsion for gliding. The improved design increases the lift-to-drag ratio from 1.56 to approximately 2.006, demonstrating the aerodynamic gains achievable through passive geometric refinement. The findings highlight the dual importance of optimizing the sonic ring standoff distance—balancing aerodynamic heating and efficiency—and establish it as a key design objective in future waverider development.