Interaction of a Mach 1.2 Shock with Two SF6 Cylinders

This page shows simulations from the interaction of a shock with a cylinder of gas. The cylinders are composed of Sulphur Hexafluoride (SF6). The rest of the shocktube is filled with air. A shock of Mach number 1.2 is introduced into the shock tube and allowed to impact the cylinder. The experiment was carried out at Los Alamos National Lab. Experimental setup is shown here (PDF File) . Simulations were carried out with the FLASH code, Version 2.3, at the ASCI FLASH Center. The PPM method, without steeping, was used. Refinement was done on the first rather than second derivatives (which is the default for FLASH). The calculations included 2 fluids, air and SF6.

Questions to be answered

  • Do the simulations converge with increasing level of resolution? Is this convergence reflected in both external appearance as well as diagnostics such as velocity, concentration etc?

    The results below show density snapshots of the evolution of the cylinder cross-section. Clicking on the images or the "density" and other links will bring up animated 'gif' movies.

    Case 1

    The initial conditions (volume concentration through a cross-section of the cylinder) are shown here (GIF image)

    7level 8level 9 level 10 level
    Max Conc =0.6 Density Pressure Density Pressure Density Pressure
    Density
    (showing blocks)     		Vorticity Density
    (showing blocks)     		Vorticity Density
    (showing blocks)     		Vorticity
    Max Conc =0.8 Density Pressure Density Pressure Density Pressure
    Density
    (showing blocks)     		Vorticity Density
    (showing blocks)     		Vorticity Density
    (showing blocks)     		Vorticity
    3D run (4 levels) Density      

    Case 2

    The initial conditions (volume concentration through a cross-section of the cylinder) are shown here (GIF image)

    7level 8level 9 level 10 level
    Max Conc =0.6 Density Pressure Density Pressure
    Density
    (showing blocks)     		Vorticity Density
    (showing blocks)     		Vorticity
    Max Conc =0.8 Density Pressure Density Pressure
    Density
    (showing blocks)     		Vorticity Density
    (showing blocks)     		Vorticity

    Case 3

    The initial conditions (volume concentration through a cross-section of the cylinder) are shown here (GIF image)

    7level 8level 9 level 10 level
    Max Conc =0.6 Density Pressure Density Pressure
    Density
    (showing blocks)     		Vorticity Density
    (showing blocks)     		Vorticity
    Max Conc =0.8 Density Pressure Density Pressure
    Density
    (showing blocks)     		Vorticity Density
    (showing blocks)     		Vorticity