Design of a variable-Mach-number waverider by the osculating-curved-cone method using a rational distribution function and incorporating the equilibrium-gas model

TL;DR

This paper introduces a new design method for variable-Mach-number hypersonic waveriders considering real-gas effects, using a rational function for Mach distribution to optimize aerodynamic performance across varying speeds.

Contribution

It proposes a novel rational function-based Mach-number distribution method for designing variable-Mach waveriders that incorporate equilibrium-gas effects, improving geometric and aerodynamic balance.

Findings

Waveriders with equilibrium-gas models differ in geometry and aerodynamics from ideal-gas designs.

Rational function-based Mach distribution yields more balanced and wing-like structures.

Designs with rational functions perform better under off-design conditions.

Abstract

When a waverider flies at hypersonic speed, the thermodynamic properties of the surrounding gas change because of the rapid increase in temperature, so it is reasonable to consider real-gas effects in the vehicle design. In addition, a hypersonic waverider usually travels at varying speed during flight, and deviating from the default speed designed in terms of a constant Mach number often creates difficulties in preserving the expected performance. Therefore, research on the design of variable-Mach-number waveriders considering equilibrium-gas effects is important for applications. In this paper, a design method for a variable-Mach-number osculating-curved-cone waverider (VMOCCW) considering equilibrium-gas effects is introduced, then the influences of different gas models on the waverider design are studied by taking a VMOCCW designed with a linear Mach-number distribution as an example. Furthermore, a new Mach-number distribution method is proposed by using a parameterized rational function, which is combined with different gas models to achieve VMOCCW design. For comparison, waveriders designed with quadratic concave and convex increasing functions are also selected for comparison of their layouts and aerodynamic performances under design and off-design conditions. The results show that waveriders designed with the equilibrium-gas model exhibit differences in geometric features (e.g., volume and volumetric efficiency) and aerodynamic characteristics (e.g., lift-to-drag ratio and pitching moment coefficient) compared to those designed with the ideal-gas model. Specifically, waveriders designed with a rational function for the Ma distribution have a wing-like structure, and overall they have more-balanced geometric and aerodynamic characteristics than those designed with quadratic concave and convex functions.