Nozzle geometry-induced vortices in supersonic wind tunnels
| Autor: | John A. Benek, Kshitij Sabnis, Holger Babinsky, Daniel Galbraith |
|---|---|
| Přispěvatelé: | Sabnis, Kshitij [0000-0001-7609-2923], Babinsky, Holger [0000-0002-7647-7126], Apollo - University of Cambridge Repository |
| Rok vydání: | 2021 |
| Předmět: |
020301 aerospace & aeronautics
Supersonic wind tunnel Materials science Nozzle 4001 Aerospace Engineering Aerospace Engineering 02 engineering and technology Mechanics Vorticity 01 natural sciences 010305 fluids & plasmas Vortex Physics::Fluid Dynamics symbols.namesake Cross section (physics) 0203 mechanical engineering Mach number 4012 Fluid Mechanics and Thermal Engineering Schlieren Condensed Matter::Superconductivity 0103 physical sciences symbols Reynolds-averaged Navier–Stokes equations 40 Engineering |
| Popis: | Streamwise-coherent structures were observed in schlieren images of a Mach 2.5 flow in an empty supersonic wind tunnel with a rectangular cross section. These features are studied using Reynolds-averaged Navier–Stokes computations in combination with wind-tunnel experiments. The structures are identified as regions of streamwise vorticity embedded in the sidewall boundary layers. These vortices locally perturb the sidewall boundary layers, and they can increase their thickness by as much as 37%. The vortices are caused by a region of separation upstream of the nozzle where there is a sharp geometry change, which is typical in supersonic wind tunnels with interchangeable nozzle blocks. Despite originating in the corners, the vortices are transported by secondary flows in the sidewall boundary layers so they end up near the tunnel center height, well away from any corners. The successful elimination of these sidewall vortices from the flow is achieved by replacing the sharp corner with a more rounded geometry so that the flow here remains attached. |
| Databáze: | OpenAIRE |
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