Uses arg names instead of underscore because it breaks (unsure why not caught by tests). Also renamed the rate-of-strain tensor function to S.

Author: b-fg

src/Flow.jl

@@ -64,7 +64,7 @@ upperBoundary!(r,u,Φ,ν,i,j,N,::Val{true}) = @loop r[I-δ(j,I),i] -= Φ[CIj(j,I
 
 Adds a space-time acceleration field g(i,x,t) and velocity field U(i,x,t) such that `rᵢ += gᵢ(i,x,t)+dUᵢ(i,x,t)/dt` at time `t=sum(dt)` to vector field `r`.
 """
-accelerate!(_,_,::Nothing,::Union{Nothing,Tuple}) = nothing
+accelerate!(r,t,::Nothing,::Union{Nothing,Tuple}) = nothing
 accelerate!(r,t,f) = for i ∈ 1:last(size(r))
     @loop r[I,i] += f(i,loc(i,I,eltype(r)),t) over I ∈ CartesianIndices(Base.front(size(r)))
 end
@@ -181,5 +181,5 @@ end
 User defined function using `udf::Function` to operate on `flow::Flow` during the predictor and corrector step, in sync with time `t`.
 Keyword arguments must be passed to `sim_step!` for them to be carried over the actual function call.
 """
-udf!(_,::Nothing,_) = nothing
-udf!(flow::Flow,force!::Function,t; kwargs...) = force!(flow,t; kwargs...)
+udf!(flow,::Nothing,t; kwargs...) = nothing
+udf!(flow,force!::Function,t; kwargs...) = force!(flow,t; kwargs...)

src/Metrics.jl

@@ -100,12 +100,12 @@ function pressure_force(p,df,body,t=0,T=promote_type(Float64,eltype(p)))
 end
 
 """
-    ∇²u(I::CartesianIndex,u)
+    S(I::CartesianIndex,u)
 
 Rate-of-strain tensor.
 """
-∇²u(I::CartesianIndex{2},u) = @SMatrix [∂(i,j,I,u)+∂(j,i,I,u) for i ∈ 1:2, j ∈ 1:2]
-∇²u(I::CartesianIndex{3},u) = @SMatrix [∂(i,j,I,u)+∂(j,i,I,u) for i ∈ 1:3, j ∈ 1:3]
+S(I::CartesianIndex{2},u) = @SMatrix [0.5*(∂(i,j,I,u)+∂(j,i,I,u)) for i ∈ 1:2, j ∈ 1:2]
+S(I::CartesianIndex{3},u) = @SMatrix [0.5*(∂(i,j,I,u)+∂(j,i,I,u)) for i ∈ 1:3, j ∈ 1:3]
 """
    viscous_force(sim::Simulation)