Shock energy computer simulation

The adiabatic collapse preserves this relation but drives the total gravitational energy to above 1053 ergs. Thus, the shock energy for a viable prompt explosion, 2 X 1051 ergs, is small in comparison to the internal or gravitational energy. Simulation must be accurate both in computation and in the input physics. 

Experiments have not yet confirmed this model. However, computer simulations have been done that illustrate the behavior. These use a version of the SALE code developed at Los Alamos for two-dimensional, time-dependent compressible flow in either Eulerian or Lagrangian coordinates. It incorporates artificial viscosity to accommodate shock fronts. The equation of state used is the Van der Waals equation as generalized by Callen to include the internal energy. ... 

The reaction NH2 + O2 was studied at high temperatures in shock waves [66 to 68]. The induction period for the appearance of OH absorption and the consumption of NH3 was measured in shock-heated NH3-O2 mixtures in the temperature range 1500 to 2800 K an activation energy of = 178 kJ/mol was obtained for the reaction NH2 + 02 NH + H02 [67]. The kinetics of ammonia oxidation in reflected shock waves was followed by observing the induction period. Computer simulation of the NH3-O2 system with the reaction scheme... 

In this section, we discuss the role of numerical simulations in studying the response of materials and structures to large deformation or shock loading. The methods we consider here are based on solving discrete approximations to the continuum equations of mass, momentum, and energy balance. Such computational techniques have found widespread use for research and engineering applications in government, industry, and academia. 

The scaled coordinate scheme applies strain uniformly throughout the computational cell, which is typically several lattice units or more in each dimension. The volume degrees of freedom may therefore be poorly coupled into very short spatial wavelength phonons which may be important in transfer of energy. Shock fronts in NEMD simulations in perfect crystals... 

---