Analysis of gas-dynamic interactions with intense optical beams

Laser propulsion - Research status and needs

“…48 This can also be achieved using upwind differencing, which can be implemented as an optionally high-order differencing of pressure and convective terms in the equation system. 49 This method allows monotonic capturing of a shock wave, if it occurs, and true physical zonal dependence, and removes the cell Reynolds number restriction. Another convergence technique consists of changing the flowfield (by adding numerical viscosity) until convergence can be attained.…”

“…The coupling between flowfield and laser energy is modeled by either discretizing the incident radiation field into rays and using Beer law for each ray 48 or using a differential form of the incident radiation equation which allows a coupled solution of the incident radiation and gas dynamic equations on the same grid. 49 The second laser interaction model uses the steady, axisymmetric, laminar flow Navier-Stokes equations for compressible, variable property flow to simulate laser-sustained plasmas. 50 The thermophysical and optical properties incorporated in the calculations are fully temperature and pressure dependent, based on the local thermodynamic equilibrium.…”