Unsteady Navier-Stokes simulations of regular-to-Mach reflection transition on an ideal surface

Shock Waves ◽  
2009 ◽  
pp. 1543-1548
Author(s):  
E. Timofeev ◽  
A. Merlen
Keyword(s):  
Mach Reflection ◽  
Navier Stokes ◽  
Reflection Transition

The persistence of regular reflection during strong shock diffraction over rigid ramps

2001 ◽  
Vol 431 ◽  
pp. 273-296 ◽  
Author(s):  
L. F. HENDERSON ◽  
K. TAKAYAMA ◽  
W. Y. CRUTCHFIELD ◽  
S. ITABASHI
Keyword(s):  
Stokes Equations ◽  
Mach Reflection ◽  
Strong Shock ◽  
Navier Stokes ◽  
Regular Reflection ◽  
Navier Stokes Equations ◽  
Von Neumann ◽  
Initial Appearance ◽  
Self Similar ◽  
Initial Shock

We report on calculations and experiments with strong shocks diffracting over rigid ramps in argon. The numerical results were obtained by integrating the conservation equations that included the Navier–Stokes equations. The results predict that if the ramp angle θ is less than the angle θe that corresponds to the detachment of a shock, θ < θe, then the onset of Mach reflection (MR) will be delayed by the initial appearance of a precursor regular reflection (PRR). The PRR is subsequently swept away by an overtaking corner signal (cs) that forces the eruption of the MR which then rapidly evolves into a self-similar state. An objective was to make an experimental test of the predictions. These were confirmed by twice photographing the diffracting shock as it travelled along the ramp. We could get a PRR with the first exposure and an MR with the second. According to the von Neumann perfect gas theory, a PRR does not exist when θ < θe. A viscous length scale xint is a measure of the position on the ramp where the dynamic transition PRR → MR takes place. It is significantly larger in the experiments than in the calculations. This is attributed to the fact that fluctuations from turbulence and surface roughness were not modelled in the calculations. It was found that xint → ∞ as θ → θe. Experiments were done to find out how xint depended on the initial shock tube pressure p0. The dependence was strong but could be greatly reduced by forming a Reynolds number based on xint. Finally by definition, regular reflection (RR) never interacts with a boundary layer, while PRR always interacts; so they are different phenomena.

scholarly journals Unsteady Transition From a Mach to a Regular Shockwave Intersection

2021 ◽  
Vol 16 ◽  
pp. 153-158
Author(s):  
S. J. Karabelas ◽  
N.C. Markatos
Keyword(s):  
Supersonic Flow ◽  
Numerical Simulations ◽  
Deflection Angle ◽  
Mach Reflection ◽  
Single Point ◽  
Research Work ◽  
Mach Disk ◽  
Navier Stokes ◽  
The Deflection Angle ◽  
To Come

The purpose of this research work is to perform accurate numerical computations of supersonic flow in a converging nozzle and specifically to study Mach-disks. The latter process has been widely studied over the last years. In the present study numerical simulations are performed for transient supersonic flow, tracing the transition from a Mach reflection to a regular one. This has been done by enforcing the walls of a converging nozzle to come closer together, changing the deflection angle with time. Viscosity was taken into account and the full Navier- Stokes have been solved. The results obtained clearly show the gradual extinction of the Mach disk and the eventual wave intersection to a single point

scholarly journals Hysteresis processes in the regular reflection↔Mach reflection transition in steady flows

2002 ◽  
Vol 38 (4-5) ◽  
pp. 347-387 ◽  
Author(s):  
G Ben-Dor ◽  
M Ivanov ◽  
E.I Vasilev ◽  
T Elperin
Keyword(s):  
Mach Reflection ◽  
Steady Flows ◽  
Regular Reflection ◽  
Reflection Transition

Reconsideration of oblique shock wave reflections in steady flows. Part 1. Experimental investigation

1995 ◽  
Vol 301 ◽  
pp. 19-35 ◽  
Author(s):  
A. Chpoun ◽  
D. Passerel ◽  
H. Li ◽  
G. Ben-Dor
Keyword(s):  
Shock Wave ◽  
State Of The Art ◽  
Mach Reflection ◽  
Oblique Shock Wave ◽  
Steady Flows ◽  
Regular Reflection ◽  
Wave Reflections ◽  
Supersonic Wind Tunnel ◽  
Reflection Transition ◽  
Reflecting Surfaces

The reflection of shock waves over straight reflecting surfaces in steady flows was investigated experimentally using the supersonic wind tunnel of Laboratoire d'Aerothermique du CNRS, Meudon, France. The results for a flow Mach number M0 = 4.96 contradict the state of the art regarding the regular [harr ] Mach reflection transition in steady flows. Not only was a hysteresis found to exist in this transition, but, unlike previous reports, regular reflection configurations were found to be stable in the dual-solution domain in which theoretically both regular and Mach reflection are possible.

Three-dimensional shock wave reflection transition in steady flow

2018 ◽  
Vol 858 ◽  
pp. 565-587 ◽  
Author(s):  
Divek Surujhlal ◽  
Beric W. Skews
Keyword(s):  
Shock Wave ◽  
Wave Reflection ◽  
Numerical Models ◽  
Dimensional Space ◽  
Mach Reflection ◽  
Three Dimensional ◽  
Flow Fields ◽  
Shock Wave Reflection ◽  
Sweep Angle ◽  
Reflection Transition

Three-dimensional shock wave reflection comprises flow physics that is significantly different from the well-documented two-dimensional cases in a number of aspects. The most important differentiating factor is the sweep of the shock system. In particular, this work examines the nature of flow fields in which there is a transition of shock reflection configuration in three-dimensional space. The flow fields investigated have been made to exist in the absence of edge effects influencing the shock interaction and transition, as found previously to exist in conventional double-wedge studies. In general, the shock configurations are those with central regular and peripheral Mach reflection portions. It is shown that the sweep angle of the portions on either side of the transition point is subject to a cusp, as per an analytical model that is developed. This is confirmed with the use of numerical models with additional evidence provided by experimental results using oblique shadow photography. Further application of the principles of three-dimensional shock analysis and those pertaining to the sweep cusp model yield important insights regarding the overall shock geometry and that at transition.

Downstream pressure induced hysteresis in the regular ↔ Mach reflection transition in steady flows

1997 ◽  
Vol 9 (10) ◽  
pp. 3096-3098 ◽  
Author(s):  
G. Ben-Dor ◽  
T. Elperin ◽  
H. Li ◽  
E. Vasiliev
Keyword(s):  
Mach Reflection ◽  
Steady Flows ◽  
Reflection Transition

Regular to Mach reflection transition in truly nonstationary flows - Influence of surface roughness

AIAA Journal ◽  
1981 ◽  
Vol 19 (9) ◽  
pp. 1238-1240 ◽  
Author(s):  
K. Takayama ◽  
G. Ben-Dor ◽  
J. Gotoh
Keyword(s):  
Surface Roughness ◽  
Mach Reflection ◽  
Reflection Transition
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