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Title: A numerical study of shock-acceleration of a diffuse helium cylinder

Conference ·
OSTI ID:114554

The development of a shock-accelerated diffuse Helium cylindrical inhomogeneity is investigated using a new numerical method. The new algorithm is a higher-order Godunov implementation of the so-called multi-fluid equations. This system correctly models multiple component mixtures by accounting for differential compressibility effects. This base integrator is embedded in an implementation of adaptive mesh refinement (AMR) that allows efficient increase in resolution where the computational effort is concentrated where high accuracy, or increased resolution, are required. Qualitative and quantitative comparison with previous experimental data is excellent. The simulations show that counter-sign vortex blobs are deposited in the jet core by baroclinic generation of the curved shock wave as it traverses the jet. This vorticity deposition occurs over timescales that scale with the shock passage time ({approximately} 10{mu}sec). Three phases of development are identified and characterized. The first is the weak deformation (WD) phase, where there is weak distortion of the Helium jet due to weak vorticity induced velocity effects. The second phase is the strong deformation (SD) phase where there is large distortion for the jet and the vortex blobs due to large induced velocity effects. The last is a relaxation/reorganization (RR) phase where the vorticity field reorganizes into point-like vortex pair.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States); Department of Defense, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
114554
Report Number(s):
UCRL-JC-122065; CONF-9507152-4; ON: DE96001317; TRN: 96:000006
Resource Relation:
Conference: 20. international symposium on shock waves, Pasadena, CA (United States), 24-28 Jul 1995; Other Information: PBD: Aug 1995
Country of Publication:
United States
Language:
English