From 28253f98ebd819984428b0009281733d0b99fea0 Mon Sep 17 00:00:00 2001
From: akshaysridhar <asridhar@caltech.edu>
Date: Tue, 17 Dec 2024 15:10:13 -0800
Subject: [PATCH] 	modified:   config/default_configs/default_config.yml 
 modified:   config/model_configs/sphere_baroclinic_wave_rhoe_equilmoist.yml 
 modified:   examples/Manifest.toml 	modified:  
 src/prognostic_equations/implicit/implicit_tendency.jl 	modified:  
 src/utils/abbreviations.jl

	modified:   NEWS.md

Fixes

Make default

Fixes
---
 NEWS.md                                               |  6 ++++++
 config/default_configs/default_config.yml             |  8 ++++----
 .../implicit/implicit_tendency.jl                     | 11 +++++++++++
 src/utils/abbreviations.jl                            |  5 +++++
 4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 75add12f58..0b54101004 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -9,6 +9,12 @@ v0.28.1
 -------
 ### Features
 
+### Add van Leer class operator
+
+Added a new vertical transport option `vanleer_limiter` (for tracer and energy variables)
+which uses methods described in Lin et al. (1994) to apply slope-limited upwinding. Adds 
+operator 
+
 ### Read initial conditions from NetCDF files
 
 Added functionality to allow initial conditions to be overwritten by
diff --git a/config/default_configs/default_config.yml b/config/default_configs/default_config.yml
index 6ae4a62206..345ae8b7b6 100644
--- a/config/default_configs/default_config.yml
+++ b/config/default_configs/default_config.yml
@@ -206,11 +206,11 @@ viscous_sponge:
   help: "Viscous sponge [`true`, `false` (default)]"
   value: false
 tracer_upwinding:
-  help: "Tracer upwinding mode [`none` (default), `first_order` , `third_order`, `boris_book`, `zalesak`]"
-  value: none
+  help: "Tracer upwinding mode [`none` (default), `first_order` , `third_order`, `boris_book`, `zalesak`, `vanleer_limiter`]"
+  value: vanleer_limiter
 energy_upwinding:
-  help: "Energy upwinding mode [`none` (default), `first_order` , `third_order`, `boris_book`, `zalesak`]"
-  value: none
+  help: "Energy upwinding mode [`none` (default), `first_order` , `third_order`, `boris_book`, `zalesak`, `vanleer_limiter`]"
+  value: vanleer_limiter
 orographic_gravity_wave:
   help: "Orographic drag on horizontal mean flow [`nothing` (default), `gfdl_restart`, `raw_topo`]"
   value: ~
diff --git a/src/prognostic_equations/implicit/implicit_tendency.jl b/src/prognostic_equations/implicit/implicit_tendency.jl
index 2eddfea985..189df5c4f9 100644
--- a/src/prognostic_equations/implicit/implicit_tendency.jl
+++ b/src/prognostic_equations/implicit/implicit_tendency.jl
@@ -73,6 +73,17 @@ vertical_transport!(
     ::Val{:first_order},
     ᶜdivᵥ,
 ) = @. ᶜρχₜ += -coeff * (ᶜdivᵥ(ᶠwinterp(ᶜJ, ᶜρ) * ᶠupwind1(ᶠu³, ᶜχ)))
+vertical_transport!(
+    coeff,
+    ᶜρχₜ,
+    ᶜJ,
+    ᶜρ,
+    ᶠu³,
+    ᶜχ,
+    dt,
+    ::Val{:vanleer_limiter},
+    ᶜdivᵥ,
+) = @. ᶜρχₜ += -coeff * (ᶜdivᵥ(ᶠwinterp(ᶜJ, ᶜρ) * ᶠlin_vanleer(ᶠu³, ᶜχ, dt)))
 vertical_transport!(
     coeff,
     ᶜρχₜ,
diff --git a/src/utils/abbreviations.jl b/src/utils/abbreviations.jl
index 8b686bc2e9..7f9442cb97 100644
--- a/src/utils/abbreviations.jl
+++ b/src/utils/abbreviations.jl
@@ -85,6 +85,11 @@ const ᶠfct_zalesak = Operators.FCTZalesak(
     bottom = Operators.FirstOrderOneSided(),
     top = Operators.FirstOrderOneSided(),
 )
+const ᶠlin_vanleer = Operators.LinVanLeerC2F(
+    bottom = Operators.FirstOrderOneSided(),
+    top = Operators.FirstOrderOneSided(),
+    constraint = Operators.MonotoneLocalExtrema(), # (Mono5)
+)
 
 const ᶜinterp_matrix = MatrixFields.operator_matrix(ᶜinterp)
 const ᶜleft_bias_matrix = MatrixFields.operator_matrix(ᶜleft_bias)