Examples

Unsteady Supersonic flow over parabolic 20% bump

GRESSIER Jérémie — 2011-09-01T22:00:00Z

Case description

20% bump in a channel
inviscid flow
unsteady upstream Mach number (sinusoidal oscillation from 3 to 2.4 to 3.)

MACH=3.+.6*(cos((t-.1)*6.28)-1.)*step((t-.1)*(1.1-t))

Numerical parameters

1600x320 quad mesh
morphing functions are

MORPH_X = 5*X MORPH_Y = Y+step(1-(sqr(x-.4)/0.04))*(1-sqr(x-.4)/0.04)*.2*(1-Y)
2nd order explicit Runge-Kutta, CFL=1
HLLC scheme, MUSCL extrapolation, 3rd order Kim limiter

Results

Ressources

An example of parameter file (main.rpm):

BLOCK:PROJECT 
 NZONE = 1 
 COORD = 2D 
 TIME = UNSTEADY 
 !RESIDUALS = 1.e-8
 DURATION = 2.
 NCYCLE = 100

ENDBLOCK 



BLOCK:OUTPUT 
 FORMAT = VTK-BIN
 FILE = "C2"
 PERIOD = 1 

ENDBLOCK



BLOCK:ZONE 
 NAME = "" 
 SOLVER = EULER 

ENDBLOCK



BLOCK:MESH
 FORMAT = INTERNAL
 FILE = "quad200x40.tym" 
 MORPH_X = 5*X
 MORPH_Y = Y+step(1-(sqr(x-.4)/0.04))*(1-sqr(x-.4)/0.04)*.2*(1-Y)

ENDBLOCK



BLOCK:MODEL
 DYNAMICS = EULER
 GAS = AIR

ENDBLOCK



BLOCK:TIME_PARAM 
 METHOD = RK2
 CFL = 1.
 RESIDUALS = .1

ENDBLOCK



BLOCK:SPAT_PARAM 
 SCHEME = HLLC
 HIGHRES = MUSCL
 LIMITER = ALBADA

ENDBLOCK



BLOCK:INIT
 P = 1.0E5
 T = 300.
 MACH = 3.
 DIRECTION = (1., 0., 0.)

ENDBLOCK



BLOCK:BOCO
 FAMILY = IMIN
 TYPE = SUPERSONIC_INLET
 PI = 1.E5
 TI = 300.
 MACH = 3.+.6*(cos((t-.1)*6.28)-1.)*step((t-.1)*(1.1-t))
 DIRECTION = ( 1., 0., 0.)

ENDBLOCK



BLOCK:BOCO
 FAMILY = IMAX
 TYPE = SUPERSONIC_OUTLET

ENDBLOCK



BLOCK:BOCO
 FAMILY = JMIN
 TYPE = SYMMETRY

ENDBLOCK



BLOCK:BOCO
 FAMILY = JMAX
 TYPE = SYMMETRY

ENDBLOCK

Supersonic reflexion on 10° wedge

GRESSIER Jérémie — 2010-06-01T14:00:00Z

Case description

Shock reflexion in a channel which section is reduced by a 10° wedge. The upstream flow is Mach 2. One can observe (weak) shock reflexions, an expansion fan and its interaction with shock waves.

(highly refined) First order computation

The computation is fully converged to 6 orders of magnitude (local time stepping with explicit integration method). The numerical scheme is the only first order HLLC.
The mesh has been automatically refined 4 times with SPLIT=ISO-TRI option (459k cells).

Second order SVM computation

The computation is fully converged to 6 orders of magnitude (local time stepping with explicit integration method). The numerical scheme is HLLC with 2nd order SVM extrapolation (without limiters). The original mesh has 1792 triangles; the SVM mesh has 5376 (quad) CV.

Ressources

The mesh is available in the mesh repository.

The parameter file (main.rpm) for SVM computation is

BLOCK:PROJECT 
 NZONE = 1 
 COORD = 2D 
 TIME = STEADY 
 RESIDUALS = 1.e-6

ENDBLOCK 



BLOCK:OUTPUT 
 FORMAT = VTK-BIN 
 FILE = "SVM2" 
 PERIOD = 1

ENDBLOCK



BLOCK:ZONE 
 NAME = "wedge10" 
 SOLVER = EULER 

ENDBLOCK



BLOCK:MESH
 FORMAT = CGNS
 FILE = "channelwedge10tri.cgns"

ENDBLOCK



BLOCK:MODEL
 DYNAMICS = EULER
 GAS = AIR

ENDBLOCK



BLOCK:TIME_PARAM
 RESIDUALS = 0.5
 DTCALC = LOCAL_STABILITY_CONDITION 
 CFL = 0.5
 CFL_MAX = 1.

ENDBLOCK



BLOCK:SPAT_PARAM 
 SCHEME = HLLC
 HIGHRES = SVM

ENDBLOCK



BLOCK:INIT
 PI = 1.E5
 TI = 300.
 MACH = 2.
 DIRECTION = (1., 0., 0.)

ENDBLOCK



BLOCK:BOCO
 FAMILY = INLET
 TYPE = SUPERSONIC_INLET
 PI = 1.E5
 TI = 300.
 MACH = 2.
 DIRECTION = (1., 0., 0.)

ENDBLOCK



BLOCK:BOCO
 FAMILY = TOP
 TYPE = SYMMETRY

ENDBLOCK



BLOCK:BOCO
 FAMILY = BOTTOM
 TYPE = SYMMETRY

ENDBLOCK



BLOCK:BOCO
 FAMILY = OUTLET
 TYPE = SUPERSONIC_OUTLET 

ENDBLOCK

Shock reflection/diffraction over pyramid

GRESSIER Jérémie — 2009-08-29T22:00:00Z

Case description

An unsteady shock wave (travelling Mach = 2.85) impacts a pyramid obstacle. A first reflexion occurs and then the shock is diffracted by the expansion from the spike of this pyramid. The 90 degrees corner trigger a separation.

Numerical parameters

600k quad mesh
second ordre MUSCL
HLLC scheme

Results

Hypersonic flow around two cylinders

GRESSIER Jérémie — 2009-08-29T21:30:00Z

Case description

inviscid flow
upstream Mach number 10

Numerical Parameters

first order HLLC scheme

Results

Multi-element inviscid flow (Suddhoo-Hall)

GRESSIER Jérémie — 2009-08-29T21:00:00Z

This inviscid flow on a multi-element airfoil is interesting since this geometry has been defined through a conformal transformation of four cylinders. Thus, a theoretical solution can be computed.
Metis partioned mesh (4 parts)

- Examples / 2D case, Inviscid flow, Steady case

Unsteady shock Wave / boundary Layer interaction

GRESSIER Jérémie — 2009-05-19T19:30:00Z

This is an unsteady viscous computation of a shock tube problem in a closed 1x1 box. The initial conditions are set with two gases at rest, same temperature but pressure and density ratio of 100 (left over right values). The Reynolds number (200) is based on the initial speed of sound and the box length. This test case has been proposed by Daru and Tenaud.

Due to the initial pressure discontinuity, a shock wave travels from left to right while accelerating the flow and creating a boundary layer on the bottom wall. Then the shock hits the right wall, crosses the initial gas interface and travels back to the left. The shock wave makes the boundary layer separate into a complex vortical flow.