Changes between Version 95 and Version 96 of u/erica/RoeSolver
- Timestamp:
- 05/31/13 14:35:15 (11 years ago)
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u/erica/RoeSolver
v95 v96 113 113 [[latex($\triangle r = r_R - r_L$)]] 114 114 115 116 = Entropy Fix =117 118 119 120 115 = A Sample Algorithm = 121 116 … … 147 142 As stated above, the Rho flux is given by: 148 143 149 [[latex( \vec{F}_{i+1/2} = \vec{F}_L + lambda*alpha*\vec{K})]]144 [[latex($\vec{F}_{i+1/2} = \vec{F}_L + lambda*alpha*\vec{K}$)]] 150 145 151 146 Where [[latex(\vec{K}_{i+1/2})]] is the vector of ''numerical'' fluxes, [[latex(\vec{F}_L)]] is the vector of physical fluxes for the left state, lambda and [[latex(\vec{K})]] are the eigenvalues and eigenvectors, and alpha is the wave speed, all with corresponding expressions given in detail above. … … 153 148 For the case of sonic rarefactions, the lambda in the above equation for Roe's flux must be adjusted, and following the Harten-Hyman approach, is taken to be: 154 149 155 [[latex( \lambda ' = (u_L-a_L)*\frac{ustar-astarL-\lambda}{ustar-astarL-u_L+a_L}]]150 [[latex($\lambda ' = (u_L-a_L)*\frac{ustar-astarL-\lambda}{ustar-astarL-u_L+a_L}$)]] 156 151 157 152 for a left sonic rarefaction. For a right sonic rarefaction, the coefficients are slightly adjusted. Note that the entropy fix requires estimates for the velocity and sound speed of the star region, ustar and astarL. We get estimates of these using the Roe approach for linearizing the Euler equations. They are listed in Toro, section 11.4.3.