diff --git a/src/equations/polytropic_euler_2d.jl b/src/equations/polytropic_euler_2d.jl index f5d2f7b0bad..b3b888ba95d 100644 --- a/src/equations/polytropic_euler_2d.jl +++ b/src/equations/polytropic_euler_2d.jl @@ -301,6 +301,46 @@ end return abs(v1) + c, abs(v2) + c end +# Calculate maximum wave speed for local Lax-Friedrichs-type dissipation as the +# maximum velocity magnitude plus the maximum speed of sound +@inline function max_abs_speed_naive(u_ll, u_rr, orientation::Integer, + equations::PolytropicEulerEquations2D) + rho_ll, v1_ll, v2_ll = cons2prim(u_ll, equations) + rho_rr, v1_rr, v2_rr = cons2prim(u_rr, equations) + + # Get the velocity value in the appropriate direction + if orientation == 1 + v_ll = v1_ll + v_rr = v1_rr + else # orientation == 2 + v_ll = v2_ll + v_rr = v2_rr + end + # Calculate sound speeds (we have p = kappa * rho^gamma) + c_ll = sqrt(equations.gamma * equations.kappa * rho_ll^(equations.gamma - 1)) + c_rr = sqrt(equations.gamma * equations.kappa * rho_rr^(equations.gamma - 1)) + + λ_max = max(abs(v_ll), abs(v_rr)) + max(c_ll, c_rr) +end + +@inline function max_abs_speed_naive(u_ll, u_rr, normal_direction::AbstractVector, + equations::PolytropicEulerEquations2D) + rho_ll, v1_ll, v2_ll = cons2prim(u_ll, equations) + rho_rr, v1_rr, v2_rr = cons2prim(u_rr, equations) + + # Calculate normal velocities and sound speed (we have p = kappa * rho^gamma) + # left + v_ll = v1_ll * normal_direction[1] + + v2_ll * normal_direction[2] + c_ll = sqrt(equations.gamma * equations.kappa * rho_ll^(equations.gamma - 1)) + # right + v_rr = v1_rr * normal_direction[1] + + v2_rr * normal_direction[2] + c_rr = sqrt(equations.gamma * equations.kappa * rho_rr^(equations.gamma - 1)) + + return max(abs(v_ll), abs(v_rr)) + max(c_ll, c_rr) * norm(normal_direction) +end + # Convert conservative variables to primitive @inline function cons2prim(u, equations::PolytropicEulerEquations2D) rho, rho_v1, rho_v2 = u