Transition Prediction in Hypersonic Boundary Layers Using Receptivity and Freestream Spectra

Area of Science:

• Aerospace Engineering
• Fluid Dynamics
• Computational Science

Background:

• Boundary-layer transition is critical for hypersonic vehicle design.
• Accurate prediction of transition onset is essential for performance and safety.

Purpose of the Study:

• To predict boundary-layer transition in hypersonic flows over a straight cone.
• To investigate the effect of cone bluntness on transition onset.
• To validate simulation methods against experimental data.

Main Methods:

• Solving 2D Navier-Stokes equations in axisymmetric coordinates.
• Utilizing a 5th-order WENO scheme for spatial discretization.
• Employing a 3rd-order TVD Runge-Kutta scheme for time integration.
• Incorporating freestream spectra, receptivity, and N-factors for prediction.

Main Results:

• N-factors increase with unit Reynolds numbers for sharp cones, plateau for blunt cones.
• Receptivity coefficients are higher for sharp cones (order 4) than blunt cones (order 1).
• Simulations closely match measured transition onset for sharp cones.
• Simulations overpredict transition onset by ~20% for blunt cones.

Conclusions:

• The simulation methodology accurately predicts transition onset for sharp cones.
• Cone bluntness significantly influences receptivity and transition location.
• Further refinement is needed for accurate prediction on blunt hypersonic bodies.