A time-dependent, three-dimensional, compressible, multicomponent, free-Lagrange code is currently under development at the Los Alamos National Laboratory. The code uses fixed-mass particles (called mass points) surrounded by median Lagrangian cells. These mass points are free to change their nearest-neighbor connections as they follow the fluid motion, which ensures accuracy in the differencing of equations and allows us to simulate flows with extreme distortions. All variables, including velocity, are mass-point centered and time-advancement is performed using the finite-volume technique. The code conserves mass, momentum, and energy exactly, except in some pathological situations. We utilize the Voronoi connections algorithm for Delaunay tetrahedralization of the median mesh during mesh generations and mesh reconnections. The code is highly vectorized and utilizes all eight processors on a Cray YMP. Also, we have recently mapped the code to the massively parallel Connection Machine. Some of the applications for the free-Lagrange method include atomspheric and ocean-circulation models, oil-reservoir and high-velocity impact simulations. These applications are in addition to our standard model problems of high-explosive driven shock-wave problems that involve high degree of deformation, shear flow, and turbulent mixing. 9 refs., 12 figs
