A Computational Analysis of Boundary Layer Instability over the BOLT Configuration

Fei Li; Meelan Choudhari; Pedro Paredes

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NASA NTRS · 20205002632

A Computational Analysis of Boundary Layer Instability over the BOLT Configuration

Fei Li·Meelan Choudhari·Pedro Paredes

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Abstract

The complex boundary layer flow over the BOLT flight configuration is known to exhibit multiple and potentially interacting instability mechanisms. This paper represents a continuation of our numerical investigation of the flow instabilities over the main test surface of the BOLT configuration by using state-of-the-art tools in multidimensional instability analysis. Specifically, the paper extends our previous computations by considering the separate effects of a nonzero angle-of-attack and a nonzero yaw on the modal instability characteristics of the boundary layer streaks adjacent to the minor-axis symmetry plane. At a selected condition from the ascent part of the anticipated flight trajectory, either type of departure from the design condition is shown to have a considerable impact on the structure of the laminar basic state and, hence, also on the amplification characteristics of the instability waves. A broader set of computations, including N-factor predictions for the relevant instabilities, will be presented in the final paper.

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Boundary layer transition Hydrodynamic instability Angle of attack Freestream Mach Number Yaw Flight trajectory Pressure sensors Direct numerical simulation Parabolized stability equations Flow conditions Adverse pressure gradient

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Fei Li, Meelan Choudhari, Pedro Paredes. 2021-01-04. A Computational Analysis of Boundary Layer Instability over the BOLT Configuration. https://ntrs.nasa.gov/citations/20205002632

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