Enhancements to Linear Stability Solver-Based CFD-integrated Transition Prediction for High-Speed Flows

What is it about?

High-speed flight systems experience significantly greater heat loads when the boundary-layer flow over the vehicle surface transitions from laminar to turbulent state. Transition onset can be correlated with the amplification of boundary-layer instabilities up to the measured transition location. However, a key hurdle is to determine the critical level of this amplification, which depends on the disturbance environment and can vary greatly between facilities. Our approach addresses this gap by proposing a closed-form correlation that utilizes easily accessible inputs such as noise levels, freestream Mach number, and facility dimension. We demonstrate that the correlation achieves good accuracy across an extensive database of wind tunnel experiments for simple geometries. By avoiding the need for case-specific precursor stability analysis, such correlations can open the door to automated transition prediction in computational fluid dynamics (CFD) for modest computational costs. This development improves the physical fidelity of hypersonic transition prediction while making it suitable for integration into routine CFD workflow. The example computations illustrate the coupling of CFD tools, stability analysis, and the new correlation to predict laminar-turbulent transition without user intervention.

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Photo by Hermeus on Unsplash

Photo by Hermeus on Unsplash