put lower threshold on entropy AV

src/HRSC/ev.jl

@@ -62,10 +62,17 @@ function compute_viscosity!(
 
   # upper bound on AV
   maxabs_v = vec(maximum(abs.(v), dims=1))
-  mu_max = @. cmax * maxabs_v * dl / N
+  (mu_max,) = @. cmax * maxabs_v * dl / N
+
+  # threshold on AV
+  (mu_min,) = 0.01 * mu_max
 
   # final AV
-  @. mu = min(mu_e, mu_max)
+  # @. mu = min(mu_e, mu_max)
+  for i in eachindex(mu_e)
+    mui = min(mu_e[i], mu_max)
+    mu[i] = mui >= mu_min ? mui : 0.0
+  end
 
   return true
 end