Unsteady aerodynamic modeling of variable-sweep wings based on the stochastic Hierarchical Kriging method

Morphing vehicles possess broad speed capability and an extensive flight envelope, necessitating aerodynamic configurations that retain favourable performance across a wide spectrum of Mach numbers (Ma). To meet this requirement, the present study introduces a variable-sweep angle vehicle (VSAV) designed to deliver optimal performance throughout an extended velocity range. Using this platform as a baseline, we analyse the unsteady aerodynamic forces generated by sweep angle (SA) variation, concentrating on three representative settings—20°, 40°, and 60°. The aerodynamic behaviour of each configuration is then assessed under a broad set of flight conditions. A longitudinal unsteady-aerodynamics prediction model rooted in Stochastic Hierarchical Kriging (SHK) theory is formulated, and its accuracy is verified against high-fidelity numerical simulations. The findings show that each SA configuration attains peak aerodynamic efficiency in a distinct flight regime, and that the proposed model accurately predicts the VSAV’s longitudinal unsteady aerodynamics. Consequently, the variable SA concept broadens the operational speed envelope of the VSAV, while the new prediction model substantially reduces the computational cost of estimation of unsteady forces.