m_constants.fpp.f90

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# 1 "/home/runner/work/MFC/MFC/src/common/m_constants.fpp"
!>
!! @file
!! @brief Contains constant values used throughout the code(s).
 
!> @brief Compile-time constant parameters: default values, tolerances, and physical constants
module m_constants
 
    use m_precision_select
 
    character, parameter :: dflt_char = ' '             !< Default string value
    real(wp), parameter  :: dflt_real = -1.e6_wp        !< Default real value
    real(wp), parameter  :: sgm_eps = 1.e-16_wp         !< Segmentation tolerance
    real(wp), parameter  :: chem_tolerance = 1.e-16_wp  !< Speed of Sound Tolerance in Chemistry
    real(wp), parameter  :: small_alf = 1.e-11_wp       !< Small alf tolerance
    real(wp), parameter  :: pi = 3.141592653589793_wp   !< Pi
    real(wp), parameter  :: verysmall = 1.e-12_wp       !< Very small number
    !> Radius cutoff to avoid division by zero for 3D spherical harmonic patch (geometry 14)
    real(wp), parameter :: small_radius = 1.e-32_wp
    integer, parameter  :: num_stcls_min = 5                   !< Minimum # of stencils
    integer, parameter  :: path_len = 400                      !< Maximum path length
    integer, parameter  :: name_len = 50                       !< Maximum name length
    integer, parameter  :: dflt_int = -100                     !< Default integer value
    integer, parameter  :: fourier_rings = 5                   !< Fourier filter ring limit
    integer, parameter  :: num_fluids_max = 10                 !< Maximum number of fluids in the simulation
    integer, parameter  :: num_probes_max = 10                 !< Maximum number of flow probes in the simulation
    integer, parameter  :: num_patches_max = 1000              !< Maximum number of IC patches
    integer, parameter  :: num_bc_patches_max = 10             !< Maximum number of boundary condition patches
    integer, parameter  :: max_2d_fourier_modes = 10           !< Max Fourier mode index for 2D modal patch (geometry 13)
    integer, parameter  :: max_sph_harm_degree = 5             !< Max degree L for 3D spherical harmonic patch (geometry 14)
    integer, parameter  :: pathlen_max = 400                   !< Maximum path length for STL/OBJ model files
    integer, parameter  :: nnode = 4                           !< Number of QBMM nodes
    integer, parameter  :: dflt_num_igr_iters = 2              !< number of iterations for IGR elliptic solve
    integer, parameter  :: dflt_num_igr_warm_start_iters = 50  !< default number of iterations for IGR elliptic solve
    real(wp), parameter :: dflt_alf_factor = 10._wp            !< scaling factor for IGR alpha
    integer, parameter  :: gp_layers = 3                       !< Number of ghost point layers for IBM
    !> color function gradient magnitude at which to apply the surface tension fluxes
    real(wp), parameter :: capillary_cutoff = 1.e-6
    !> Spatial support width of acoustic source, used in s_source_spatial
    real(wp), parameter :: acoustic_spatial_support_width = 2.5_wp
    real(wp), parameter :: dflt_vcfl_dt = 100._wp  !< value of vcfl_dt when viscosity is off for computing adaptive timestep size
    !> The constant to scale the spectral level at the lower frequency bound
    real(wp), parameter :: broadband_spectral_level_constant = 20._wp
    !> The spectral level constant to correct the magnitude at each frequency to ensure the source is overall broadband
    real(wp), parameter :: broadband_spectral_level_growth_rate = 10._wp
    ! Reconstruction Types
    integer, parameter :: weno_type = 1   !< Using WENO for reconstruction type
    integer, parameter :: muscl_type = 2  !< Using MUSCL for reconstruction type
    ! Interface Compression
    real(wp), parameter :: dflt_ic_eps = 1e-4_wp    !< Ensure compression is only applied to surface cells in THINC
    real(wp), parameter :: dflt_ic_beta = 1.6_wp    !< Sharpness parameter's default value used in THINC
    real(wp), parameter :: moncon_cutoff = 1e-8_wp  !< Monotonicity constraint's limiter to prevent extremas in THINC
    ! Chemistry
    real(wp), parameter :: dflt_t_guess = 1200._wp  !< Default guess for temperature (when a previous value is not available)
 
    ! IBM+STL interpolation constants
    integer, parameter  :: num_ray = 20                        !< Default number of rays traced per cell
    real(wp), parameter :: ray_tracing_threshold = 0.9_wp      !< Threshold above which the cell is marked as the model patch
    real(wp), parameter :: threshold_vector_zero = 1.e-10_wp   !< Threshold to treat the component of a vector to be zero
    real(wp), parameter :: threshold_edge_zero = 1.e-10_wp     !< Threshold to treat two edges to be overlapped
    real(wp), parameter :: initial_distance_buffer = 1.e12_wp  !< Initialized levelset distance for the shortest path pair algorithm
    ! Lagrange bubbles constants
    integer, parameter  :: mapcells = 3      !< Number of cells around the bubble where the smoothening function will have effect
    real(wp), parameter :: r_uni = 8314._wp  !< Universal gas constant - J/kmol/K
    integer, parameter  :: lag_io_vars = 21  !< Number of variables per particle for MPI_IO
 
    ! Strang Splitting constants
    real(wp), parameter :: dflt_adap_dt_tol = 1.e-4_wp   !< Default tolerance for adaptive step size
    integer, parameter  :: dflt_adap_dt_max_iters = 100  !< Default max iteration for adaptive step size
    ! Constants of the algorithm described by Heirer, E. Hairer, S. P.Norsett, G. Wanner, Solving Ordinary Differential Equations I,
    ! Chapter II.4 to choose the initial time step size for the adaptive time stepping routine
    real(wp), parameter :: threshold_first_guess = 1.e-5_wp    !< Threshold for initial step size estimate
    real(wp), parameter :: threshold_second_guess = 1.e-15_wp  !< Threshold for refined step size estimate
    real(wp), parameter :: scale_first_guess = 1.e-3_wp        !< Scale factor for initial step size
    real(wp), parameter :: scale_guess = 1.e-2_wp              !< Scale factor for step size adjustment
    real(wp), parameter :: small_guess = 1.e-6_wp              !< Minimum initial step size
 
    ! Relativity
    !> Max Newton-Raphson iterations for relativistic primitive recovery
    integer, parameter :: relativity_cons_to_prim_max_iter = 100
 
    ! Linear congruential pseudo-random number generator parameters
    integer, parameter  :: modulus = 2**30 - 1     !< PRNG modulus
    integer, parameter  :: multiplier = 1664525    !< PRNG multiplier
    integer, parameter  :: increment = 1013904223  !< PRNG increment
    integer, parameter  :: amplifier = 3**13       !< PRNG amplifier for mixing
    real(wp), parameter :: decimal_trim = 1.e5_wp  !< PRNG decimal truncation factor
 
    ! System constants
    integer, parameter :: case_file_error_code = 22  !< Exit code for case file validation errors
 
    ! Boundary condition enumeration Abbreviations CHAR - Characteristic NR - Non-reflecting SUB - subsonic SUP - supersonic FF -
    ! Force-free CP - Constant pressure
    integer, parameter :: bc_periodic = -1
    integer, parameter :: bc_reflective = -2
    integer, parameter :: bc_ghost_extrap = -3
    integer, parameter :: bc_riemann_extrap = -4
    integer, parameter :: bc_char_slip_wall = -5
    integer, parameter :: bc_char_nr_sub_buffer = -6
    integer, parameter :: bc_char_nr_sub_inflow = -7
    integer, parameter :: bc_char_nr_sub_outflow = -8
    integer, parameter :: bc_char_ff_sub_outflow = -9
    integer, parameter :: bc_char_cp_sub_outflow = -10
    integer, parameter :: bc_char_sup_inflow = -11
    integer, parameter :: bc_char_sup_outflow = -12
    integer, parameter :: bc_null = -13
    integer, parameter :: bc_axis = -14
    integer, parameter :: bc_slip_wall = -15
    integer, parameter :: bc_no_slip_wall = -16
    integer, parameter :: bc_dirichlet = -17
end module m_constants