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Shock polar investigation in supersonic rarefied gas flows over a circular cylinder

Akhlaghi, H ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1063/5.0050571
  3. Publisher: American Institute of Physics Inc , 2021
  4. Abstract:
  5. Well-known polars in classical shock wave theory, that is, flow deflection angle-shock angle (θ-β), hodograph (u*,v*), and pressure deflection (θ-P*) diagrams, are investigated for the rarefied gas flows using a recently proposed shock wave detection technique by Akhlaghi and coworkers. The agreement between the obtained polars with the analytical relations in classical shock wave theory has been shown in the continuum limit for the cases of supersonic flow over the wedge and cylinder geometries. Investigations are performed using the RGS2D direct simulation Monte Carlo solver for supersonic gas flows over a circular cylinder at continuum limit and Kn = 10-4, 10-3, 0.01, 0.03, 0.07, and 0.10. Two species of nitrogen and argon at various Mach numbers of 1.5, 3.0, and 10.0 are considered. The shock polars are investigated along bow shock waves in front of the cylinder. The results indicate that rarefaction significantly affects the shock polars. As Knudsen number increases, shock angle, maximum flow deflection angle, and aft shock pressure increase. However, velocity components after the shock wave decrease as the flow becomes more rarefied. These effects are stronger for θ-β polar under the weak shock condition. Meanwhile, they are stronger for θ-P* and hodograph polars in strong shock situations. © 2021 Author(s)
  6. Keywords:
  7. Circular cylinders ; Flow of gases ; Gases ; Kinematics ; Monte Carlo methods ; Supersonic flow ; Analytical relations ; Deflection angles ; Direct simulation Monte Carlo ; Rarefied gas flow ; Shock wave detection ; Shock wave theories ; Supersonic gas flows ; Velocity components ; Shock waves
  8. Source: Physics of Fluids ; Volume 33, Issue 5 , 2021 ; 10706631 (ISSN)
  9. URL: https://aip.scitation.org/doi/abs/10.1063/5.0050571