Pressure solvers

The discrete pressure Poisson equation

\[L p = W M F(u)\]

enforces divergence freeness. There are multiple options for solving this system.

IncompressibleNavierStokes.default_psolver — Function

default_psolver(setup)

Get default Poisson solver from setup.

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IncompressibleNavierStokes.psolver_direct — Function

poisson_direct(setup)

Create direct Poisson solver using an appropriate matrix decomposition.

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IncompressibleNavierStokes.psolver_cg — Function

psolver_cg(
    setup;
    abstol = zero(eltype(setup.grid.x[1])),
    reltol = sqrt(eps(eltype(setup.grid.x[1]))),
    maxiter = prod(setup.grid.Np),
    preconditioner = create_laplace_diag(setup),
)

Conjugate gradients iterative Poisson solver.

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IncompressibleNavierStokes.psolver_cg_matrix — Function

psolver_cg_matrix(setup; kwargs...)

Conjugate gradients iterative Poisson solver. The kwargs are passed to the cg! function from IterativeSolvers.jl.

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IncompressibleNavierStokes.psolver_spectral — Function

psolver_spectral(setup)

Create spectral Poisson solver from setup.

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IncompressibleNavierStokes.psolver_spectral_lowmemory — Function

psolver_spectral_lowmemory(setup)

Create spectral Poisson solver from setup. This one is slower than psolver_spectral but occupies less memory.

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IncompressibleNavierStokes.pressure — Function

pressure(u, temp, t, setup; psolver)

Compute pressure from velocity field. This makes the pressure compatible with the velocity field, resulting in same order pressure as velocity.

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IncompressibleNavierStokes.pressure! — Function

pressure!(p, u, temp, t, setup; psolver, F, div)

Compute pressure from velocity field. This makes the pressure compatible with the velocity field, resulting in same order pressure as velocity.

source

IncompressibleNavierStokes.poisson — Function

poisson(psolver, f)

Solve the Poisson equation for the pressure with right hand side f at time t. For periodic and no-slip BC, the sum of f should be zero.

Non-mutating/allocating/out-of-place version.