Add a test for fixed-dt RC coefs

modules/navier_stokes/test/tests/finite_volume/physics/restart/2d_channel_init.i

@@ -0,0 +1,130 @@
+### Thermophysical Properties ###
+rho = 1
+mu = 100
+
+### Simulation parameters
+inlet_velocity = 1
+side_length = 1
+restart_initial_dt = 1
+[Mesh]
+  active = 'gen'
+  [gen]
+    type = GeneratedMeshGenerator
+    dim = 2
+    xmin = 0
+    xmax = 10
+    ymin = 0
+    ymax = ${side_length}
+    nx = 100
+    ny = 20
+  []
+  [fmg_restart]
+    type = FileMeshGenerator
+    file = 2d_channel_init_exodus.e
+    use_for_exodus_restart = true
+  []
+[]
+
+[Physics]
+  [NavierStokes]
+    [Flow]
+      [all_flow]
+        compressibility = 'incompressible'
+
+        density = ${rho}
+        dynamic_viscosity = ${mu}
+
+        inlet_boundaries = 'left'
+        momentum_inlet_types = 'fixed-velocity'
+        momentum_inlet_functors = '${inlet_velocity} 0'
+
+        wall_boundaries = 'top bottom'
+        momentum_wall_types = 'noslip noslip'
+
+        outlet_boundaries = 'right'
+        momentum_outlet_types = 'fixed-pressure'
+        pressure_functors = '0'
+
+        # Make sure restart is perfect by freezing the time step dependence of
+        # the contribution to the RC coefficient by the time derivative kernel
+        time_derivative_rc_coef_fixed_dt = ${restart_initial_dt} # (s)
+        time_derivative_rc_coef_fixed_dt_start = 10
+
+        mass_advection_interpolation = 'upwind'
+        momentum_advection_interpolation = 'upwind'
+      []
+    []
+  []
+[]
+
+[Functions]
+  [grow_dt]
+    type = PiecewiseLinear
+    x = '0 10'
+    y = '0.1 10'
+  []
+  [constant]
+    type = PiecewiseConstant
+    x = '0 10'
+    y = '${restart_initial_dt} ${restart_initial_dt}'
+  []
+[]
+
+[Executioner]
+  type = Transient
+  solve_type = 'NEWTON'
+  petsc_options_iname = '-pc_type -pc_factor_shift_type'
+  petsc_options_value = 'lu NONZERO'
+  nl_abs_tol = 1e-10
+
+  line_search = 'none'
+  [TimeStepper]
+    type = FunctionDT
+    function = 'grow_dt'
+  []
+  # Enough to obtain steady state (no nonlinear iteration needed)
+  end_time = 40
+[]
+
+[Outputs]
+  # Used to set up a restart from exodus file
+  [exodus]
+    type = Exodus
+    execute_on = TIMESTEP_END
+  []
+  # Used to check results
+  csv = true
+[]
+
+[Postprocessors]
+  [min_vel_x]
+    type = ElementExtremeValue
+    variable = 'vel_x'
+    value_type = 'min'
+  []
+  [max_vel_x]
+    type = ElementExtremeValue
+    variable = 'vel_x'
+    value_type = 'max'
+  []
+  [min_vel_y]
+    type = ElementExtremeValue
+    variable = 'vel_y'
+    value_type = 'min'
+  []
+  [max_vel_y]
+    type = ElementExtremeValue
+    variable = 'vel_y'
+    value_type = 'max'
+  []
+  [min_pressure]
+    type = ElementExtremeValue
+    variable = 'pressure'
+    value_type = 'min'
+  []
+  [max_pressure]
+    type = ElementExtremeValue
+    variable = 'pressure'
+    value_type = 'max'
+  []
+[]

modules/navier_stokes/test/tests/finite_volume/physics/restart/gold/2d_channel_init_out.csv

@@ -0,0 +1,12 @@
+time,max_pressure,max_vel_x,max_vel_y,min_pressure,min_vel_x,min_vel_y
+0,0,0,0,0,0,0
+0.1,14212.706788194,1.4919498266697,0.34043711118634,60.299188126278,0.14944554792803,-0.34043711118634
+0.299,14093.89890486,1.492583174832,0.34054313371413,59.70153045387,0.14920089724169,-0.34054313371413
+0.69501,14093.890023708,1.4925835978148,0.34054306059652,59.701492548005,0.14920080194696,-0.34054306059652
+1.4830699,14093.889271499,1.4925835979685,0.34054300989256,59.701492537316,0.14920080190933,-0.34054300989256
+3.051309101,14093.888894536,1.4925835979762,0.34054298441005,59.701492537314,0.14920080190394,-0.34054298441005
+6.17210511099,14093.888705106,1.4925835979801,0.34054297160468,59.701492537314,0.14920080190123,-0.34054297160468
+10,14093.88866976,1.4925835979809,0.34054296921534,59.701492537314,0.14920080190073,-0.34054296921534
+20,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+30,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+40,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646

modules/navier_stokes/test/tests/finite_volume/physics/restart/gold/transient_from_restart.csv

@@ -0,0 +1,12 @@
+time,max_pressure,max_vel_x,max_vel_y,min_pressure,min_vel_x,min_vel_y
+0,0,0,0,0,0,0
+1,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+2,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+3,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+4,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+5,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+6,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+7,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+8,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+9,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646
+10,14093.889110909,1.4925835979718,0.34054299903646,59.701492537314,0.14920080190704,-0.34054299903646

modules/navier_stokes/test/tests/finite_volume/physics/restart/tests

@@ -64,4 +64,24 @@
       allow_unused = true
     []
   []
+  [restart_different_dt]
+    requirement = 'The system shall be able to'
+    [init]
+      type = CSVDiff
+      input = '2d_channel_init.i'
+      csvdiff = 2d_channel_init_out.csv'
+      detail = 'initialize a solution for a restart simulation using a fixed time step for the contribution to Rhie Chow coefficients,'
+    []
+    [flat_restart_different_dt]
+      type = CSVDiff
+      input = '2d_channel_init.i'
+      csvdiff = 'transient_from_restart.csv'
+      cli_args = "Physics/NavierStokes/Flow/all_flow/time_derivative_rc_coef_fixed_dt_start=1e8
+                  Mesh/active=fmg_restart
+                  Physics/NavierStokes/Flow/all_flow/initialize_variables_from_mesh_file=true
+                  Outputs/file_base=transient_from_restart
+                  Executioner/TimeStepper/function=constant Executioner/end_time=10"
+      detail = 'and restarting from such solution with a perfect, zero-residual restart.'
+    []
+  []
 []