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Add numerical support of other real types (lattice) #1991

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Jul 17, 2024
Merged

Add numerical support of other real types (lattice) #1991

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huiyuxie Jun 25, 2024
1e039c9
Merge branch 'main' into main-lattice
huiyuxie Jun 25, 2024
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Merge branch 'main' into main-lattice
huiyuxie Jul 2, 2024
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Merge branch 'main' into main-lattice
huiyuxie Jul 15, 2024
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complete equations
huiyuxie Jul 15, 2024
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Merge branch 'main' into main-lattice
huiyuxie Jul 15, 2024
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huiyuxie Jul 17, 2024
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complete 1D
huiyuxie Jul 17, 2024
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complete 2D/3D
huiyuxie Jul 17, 2024
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21 changes: 14 additions & 7 deletions src/equations/lattice_boltzmann_2d.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -101,12 +101,16 @@ function LatticeBoltzmannEquations2D(; Ma, Re, collision_op = collision_bgk,
# The relation between the isothermal speed of sound `c_s` and the mean thermal molecular velocity
# `c` depends on the used phase space discretization, and is valid for D2Q9 (and others). For
# details, see, e.g., [3] in the docstring above.
c_s = c / sqrt(3)
# c_s = c / sqrt(3)

# Calculate missing quantities
if isnothing(Ma)
RealT = eltype(u0)
c_s = c / sqrt(convert(RealT, 3))
Ma = u0 / c_s
elseif isnothing(u0)
RealT = eltype(Ma)
c_s = c / sqrt(convert(RealT, 3))
u0 = Ma * c_s
end
if isnothing(Re)
Expand All @@ -119,9 +123,10 @@ function LatticeBoltzmannEquations2D(; Ma, Re, collision_op = collision_bgk,
Ma, Re, c, L, rho0, u0, nu = promote(Ma, Re, c, L, rho0, u0, nu)

# Source for weights and speeds: [4] in the docstring above
weights = SVector(1 / 9, 1 / 9, 1 / 9, 1 / 9, 1 / 36, 1 / 36, 1 / 36, 1 / 36, 4 / 9)
v_alpha1 = SVector(c, 0, -c, 0, c, -c, -c, c, 0)
v_alpha2 = SVector(0, c, 0, -c, c, c, -c, -c, 0)
weights = SVector{9, RealT}(1 / 9, 1 / 9, 1 / 9, 1 / 9, 1 / 36, 1 / 36, 1 / 36,
1 / 36, 4 / 9)
v_alpha1 = SVector{9, RealT}(c, 0, -c, 0, c, -c, -c, c, 0)
v_alpha2 = SVector{9, RealT}(0, c, 0, -c, c, c, -c, -c, 0)
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LatticeBoltzmannEquations2D(c, c_s, rho0, Ma, u0, Re, L, nu,
weights, v_alpha1, v_alpha2,
Expand Down Expand Up @@ -154,7 +159,9 @@ A constant initial condition to test free-stream preservation.
"""
function initial_condition_constant(x, t, equations::LatticeBoltzmannEquations2D)
@unpack u0 = equations
rho = pi

RealT = eltype(x)
rho = convert(RealT, pi)
v1 = u0
v2 = u0

Expand Down Expand Up @@ -253,7 +260,7 @@ end
else
v_alpha = equations.v_alpha2
end
return 0.5 * (v_alpha .* (u_ll + u_rr) - abs.(v_alpha) .* (u_rr - u_ll))
return 0.5f0 * (v_alpha .* (u_ll + u_rr) - abs.(v_alpha) .* (u_rr - u_ll))
end

"""
Expand Down Expand Up @@ -358,7 +365,7 @@ Collision operator for the Bhatnagar, Gross, and Krook (BGK) model.
@inline function collision_bgk(u, dt, equations::LatticeBoltzmannEquations2D)
@unpack c_s, nu = equations
tau = nu / (c_s^2 * dt)
return -(u - equilibrium_distribution(u, equations)) / (tau + 1 / 2)
return -(u - equilibrium_distribution(u, equations)) / (tau + 0.5f0)
end

@inline have_constant_speed(::LatticeBoltzmannEquations2D) = True()
Expand Down
49 changes: 29 additions & 20 deletions src/equations/lattice_boltzmann_3d.jl
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Expand Up @@ -141,12 +141,16 @@ function LatticeBoltzmannEquations3D(; Ma, Re, collision_op = collision_bgk,
# The relation between the isothermal speed of sound `c_s` and the mean thermal molecular velocity
# `c` depends on the used phase space discretization, and is valid for D3Q27 (and others). For
# details, see, e.g., [3] in the docstring above.
c_s = c / sqrt(3)
# c_s = c / sqrt(3)

# Calculate missing quantities
if isnothing(Ma)
RealT = eltype(u0)
c_s = c / sqrt(convert(RealT, 3))
Ma = u0 / c_s
elseif isnothing(u0)
RealT = eltype(Ma)
c_s = c / sqrt(convert(RealT, 3))
u0 = Ma * c_s
end
if isnothing(Re)
Expand All @@ -159,21 +163,24 @@ function LatticeBoltzmannEquations3D(; Ma, Re, collision_op = collision_bgk,
Ma, Re, c, L, rho0, u0, nu = promote(Ma, Re, c, L, rho0, u0, nu)

# Source for weights and speeds: [4] in docstring above
weights = SVector(2 / 27, 2 / 27, 2 / 27, 2 / 27, 2 / 27, 2 / 27, 1 / 54, 1 / 54,
1 / 54,
1 / 54, 1 / 54, 1 / 54, 1 / 54, 1 / 54, 1 / 54, 1 / 54, 1 / 54,
1 / 54,
1 / 216, 1 / 216, 1 / 216, 1 / 216, 1 / 216, 1 / 216, 1 / 216,
1 / 216, 8 / 27)
v_alpha1 = SVector(c, -c, 0, 0, 0, 0, c, -c, c,
-c, 0, 0, c, -c, c, -c, 0, 0,
c, -c, c, -c, c, -c, -c, c, 0)
v_alpha2 = SVector(0, 0, c, -c, 0, 0, c, -c, 0,
0, c, -c, -c, c, 0, 0, c, -c,
c, -c, c, -c, -c, c, c, -c, 0)
v_alpha3 = SVector(0, 0, 0, 0, c, -c, 0, 0, c,
-c, c, -c, 0, 0, -c, c, -c, c,
c, -c, -c, c, c, -c, c, -c, 0)
weights = SVector{27, RealT}(2 / 27, 2 / 27, 2 / 27, 2 / 27, 2 / 27, 2 / 27, 1 / 54,
1 / 54,
1 / 54,
1 / 54, 1 / 54, 1 / 54, 1 / 54, 1 / 54, 1 / 54, 1 / 54,
1 / 54,
1 / 54,
1 / 216, 1 / 216, 1 / 216, 1 / 216, 1 / 216, 1 / 216,
1 / 216,
1 / 216, 8 / 27)
v_alpha1 = SVector{27, RealT}(c, -c, 0, 0, 0, 0, c, -c, c,
-c, 0, 0, c, -c, c, -c, 0, 0,
c, -c, c, -c, c, -c, -c, c, 0)
v_alpha2 = SVector{27, RealT}(0, 0, c, -c, 0, 0, c, -c, 0,
0, c, -c, -c, c, 0, 0, c, -c,
c, -c, c, -c, -c, c, c, -c, 0)
v_alpha3 = SVector{27, RealT}(0, 0, 0, 0, c, -c, 0, 0, c,
-c, c, -c, 0, 0, -c, c, -c, c,
c, -c, -c, c, c, -c, c, -c, 0)
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LatticeBoltzmannEquations3D(c, c_s, rho0, Ma, u0, Re, L, nu,
weights, v_alpha1, v_alpha2, v_alpha3,
Expand Down Expand Up @@ -206,7 +213,9 @@ A constant initial condition to test free-stream preservation.
"""
function initial_condition_constant(x, t, equations::LatticeBoltzmannEquations3D)
@unpack u0 = equations
rho = pi

RealT = eltype(x)
rho = convert(RealT, pi)
v1 = u0
v2 = u0
v3 = u0
Expand Down Expand Up @@ -243,7 +252,7 @@ end
else # z-direction
v_alpha = equations.v_alpha3
end
return 0.5 * (v_alpha .* (u_ll + u_rr) - abs.(v_alpha) .* (u_rr - u_ll))
return 0.5f0 * (v_alpha .* (u_ll + u_rr) - abs.(v_alpha) .* (u_rr - u_ll))
end

"""
Expand Down Expand Up @@ -369,7 +378,7 @@ Collision operator for the Bhatnagar, Gross, and Krook (BGK) model.
@inline function collision_bgk(u, dt, equations::LatticeBoltzmannEquations3D)
@unpack c_s, nu = equations
tau = nu / (c_s^2 * dt)
return -(u - equilibrium_distribution(u, equations)) / (tau + 1 / 2)
return -(u - equilibrium_distribution(u, equations)) / (tau + 0.5f0)
end

@inline have_constant_speed(::LatticeBoltzmannEquations3D) = True()
Expand All @@ -391,7 +400,7 @@ end
rho = density(u, equations)
v1, v2, v3 = velocity(u, equations)

return 0.5 * (v1^2 + v2^2 + v3^2) / rho / equations.rho0
return 0.5f0 * (v1^2 + v2^2 + v3^2) / rho / equations.rho0
end

# Calculate nondimensionalized kinetic energy for a conservative state `u`
Expand Down
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