Merge pull request #103 from egyaa20/AA/adaptive-dt

Add adaptive timestepping

Author: mberto79

CHANGELOG.md

@@ -6,7 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## Version [v0.5.3] - 2026-02-19
 
 ### Added
-*  No new functionality added
+*  Added optional adaptive time stepping based on Courant number control (`AdaptiveTimeStepping`) [#98](@ref)
 
 
 ### Fixed

examples/2D_flatplate_fixedT_KOmega.jl

@@ -99,7 +99,8 @@ solvers = (
         solver      = Gmres(), # Bicgstab(), Gmres()
         preconditioner = Jacobi(),
         convergence = 1e-7,
-        relax       = 0.3,
+        # relax       = 0.3,
+        relax       = 0.2,
         atol = 1e-2
     ),
     h = SolverSetup(

src/Calculate/Calculate_0_gradient.jl

@@ -255,4 +255,9 @@ function grad!(grad::Grad{Midpoint,F,R,I,M}, phif, phi, BCs, time, config) where
         correct_interpolation!(grad, phif, phi, config)
         green_gauss!(grad, phif, config)
     end
+end
+
+# This is a gradient method that does not take BCs as arguments (implicitly assuming the the gradient at boundaries is 0)
+function grad!(grad::Grad{Gauss,F,R,I,M}, phif, phi, time, config) where {F,R<:VectorField,I,M}
+    green_gauss!(grad, phif, config)
 end

src/Discretise/Discretise_1_schemes.jl

@@ -30,7 +30,7 @@ end
 @inline scheme_source!(
     term::Operator{F,P,I,Time{Euler}}, cell, cID, cIndex, prev, runtime)  where {F,P,I} = begin
         volume = cell.volume
-        vol_rdt = volume/runtime.dt
+        vol_rdt = volume/runtime.dt[1]
 
         # Increment sparse and b arrays 
         ac = vol_rdt
@@ -48,7 +48,7 @@ end
 @inline scheme_source!(
     term::Operator{F,P,I,Time{CrankNicolson}}, cell, cID, cIndex, prev, runtime)  where {F,P,I} = begin
         volume = cell.volume
-        vol_rdt = volume/runtime.dt
+        vol_rdt = volume/runtime.dt[1]
 
         # Increment sparse and b arrays 
         ac = vol_rdt

src/ModelPhysics/0_type_definition.jl

@@ -4,6 +4,7 @@ export Momentum
 export AbstractTimeModel
 export Transient, Steady
 
+
 """
     struct Physics{T,F,SO,M,Tu,E,D,BI}
         time::T
@@ -159,4 +160,4 @@ end
 mutable struct ModelState{T1}
     residuals::T1
     converged::Bool
-end
+end

src/ModelPhysics/Energy/Energy.jl

@@ -19,7 +19,6 @@ include("energy_types.jl")
 
 # Energy models
 include("Sensible_Enthalpy.jl")
-# include("Laplace_Energy.jl")
 include("Conduction.jl")
 
 # Property Models

src/ModelPhysics/Energy/Sensible_Enthalpy.jl

@@ -159,7 +159,7 @@ function energy!(
     # Kbounded = ScalarField(mesh)
     Pr = model.fluid.Pr
 
-    dt = runtime.dt
+    dt = runtime.dt[1]
 
     # Pre-allocate auxiliary variables
     TF = _get_float(mesh)

src/ModelPhysics/ModelPhysics.jl

@@ -34,4 +34,5 @@ include("Turbulence/Turbulence.jl")
 include("FluidProperties/FluidProperties.jl")
 
 
+
 end # end module

src/ModelPhysics/Turbulence/RANS_laminar.jl

@@ -102,6 +102,19 @@ function save_output(model::Physics{T,F,SO,M,Tu,E,D,BI}, outputWriter, iteration
     write_results(iteration, time, model.domain, outputWriter, config.boundaries, args...)
 end
 
+# function save_output(model::Physics{T,F,SO,M,Tu,E,D,BI}, outputWriter, iteration, time, config
+#     ) where {T,F<:Multiphase,SO,M,Tu<:Laminar,E<:Nothing,D,BI}
+
+#     args = (
+#         ("U", model.momentum.U), 
+#         ("p", model.momentum.p),
+#         ("alpha", model.fluid.alpha),
+#         ("rho", model.fluid.rho),
+#         # ("p_rgh", model.fluid.p_rgh)
+#     )
+#     write_results(iteration, time, model.domain, outputWriter, config.boundaries, args...)
+# end
+
 function save_output(model::Physics{T,F,SO,M,Tu,E,D,BI}, outputWriter, iteration, time, config
     ) where {T,F,SO,M,Tu<:Laminar,E<:Nothing,D,BI}
     args = (

src/Simulate/Simulate_0_types.jl

@@ -2,12 +2,12 @@ export Configuration
 export Hardware
 
 """
-    @kwdef struct Configuration{SC,SL,RT,HW,PP}
+    struct Configuration{SC,SL,RT,HW,PP}
         schemes::SC
         solvers::SL
         runtime::RT
         hardware::HW
-        postprocess::PP = nothing
+        postprocess::PP
     end
 
 The `Configuration` type is passed to all flow solvers and provides all the relevant information to run a simulation. 
@@ -29,16 +29,29 @@ config = Configuration(
     solvers=solvers, schemes=schemes, runtime=runtime, hardware=hardware, boundaries=BCs)
 ```
 """
-@kwdef struct Configuration{SC,SL,RT,HW,BC,PP}
+struct Configuration{SC,SL,RT,HW,BC,PP}
     schemes::SC
     solvers::SL
     runtime::RT
     hardware::HW
     boundaries::BC
-    postprocess::PP = nothing
+    postprocess::PP
 end
 Adapt.@adapt_structure Configuration
 
+Configuration(; schemes, solvers, runtime, hardware, boundaries, postprocess=nothing) = begin
+Configuration(
+    schemes,
+    solvers,
+    adapt(hardware.backend, runtime),
+    hardware,
+    boundaries,
+    postprocess
+)
+end
+
+
+
 
 """
     hardware = Hardware(backend, workgroup)