Browsing by Author "Stollery, John L."

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    Drag estimation on wedge-shaped protuberances in high-speed flows
    (AIAA, 2020-01-05) Kshitij, Abhinav; Prince, Simon A.; Stollery, John L.
    A semi-empirical method is developed to estimate drag on wedge-shaped projections in hypersonic flow. Force balance measurements from gun tunnel tests directly measure total drag on blunt wedges, where the boundary layer and the entropy layer are weakly coupled. Detailed flowfield analysis from numerical simulations provides estimated locations of peak pressure ratio and skin friction. Schlieren images are used for detecting incipient separation in incoming flows with laminar and turbulent boundary layers. Test results indicate the presence of local hotspots at reattachment points of strong detached shocks on the wedge compression ramp, and of primary and secondary vortical structures around lateral faces. Total drag is found to decrease with decreasing bluntness but increasing slenderness in wedges tend to increase skin friction drag.
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    A simple method for drag estimation for wedge-like fairings in hypersonic flow
    (Cambridge University Press, 2021-03-23) Kshitij, A.; Prince, Simon A.; Stollery, John L.; de la P. Ricón, F.
    The addition of wedge-like fairings onto the side of missiles and space launch vehicles, to shield devices such as cameras and reaction jet nozzles, creates additional drag particularly when in supersonic and hypersonic freestream flow. An experimental and computational study was performed in order to obtain aerodynamic data on simple representative configurations in order to test the accuracy of simple theories for the drag increment due to these types of fairings. A semi-empirical method to estimate drag on wedge-shaped projections is presented, which may be used by missile designers to provide predictions of the drag increment due to wedge-like fairings. The method is shown to be valid where the wedge width is much smaller than body diameter, and across the Mach number range 4 – 8.2, but is likely to be valid for higher Mach numbers. Drag coefficient is found to increase with increasing wedge angle and reducing wedge slenderness, although increasing slenderness tends to increase skin friction drag.