Add variable mass example (#90)

* add variable mass example

* misc clean up and formatting

* readme

* add note on model version to readme

* Update after review

* Update, clean up, and add tests

* remove clear

* revert gitignore

---------

Co-authored-by: akeeste <akeeste@sandia.gov>

Author: jtgrasb

…le_Hydro/Passive_Yaw/TestVariableHydro.m Variable_Hydro/TestVariableHydro.mVariable_Hydro/Passive_Yaw/TestVariableHydro.m renamed to Variable_Hydro/TestVariableHydro.m Variable_Hydro/Passive_Yaw/TestVariableHydro.m renamed to Variable_Hydro/TestVariableHydro.m

@@ -3,12 +3,14 @@
     properties
         OriginalDefault
         testDir
-        h5Dir = fullfile("hydroData")
-        h5Name = 'oswec_0.h5'
+        h5DirPY = ['Passive_Yaw',filesep,'hydroData']
+        h5NamePY = 'oswec_0.h5'
         outName = 'oswec.out'
+        h5DirVM = ['Variable_Mass',filesep,'hydroData']
+        h5NameVM = 'draft1.h5'
+
     end
 
-    
     methods (Access = 'public')
         function obj = TestVariableHydro
             obj.testDir = fileparts(mfilename('fullpath'));
@@ -27,9 +29,19 @@ function captureVisibility(testCase)
             testCase.OriginalDefault = get(0, 'DefaultFigureVisible');
         end
 
-        function runBemio(testCase)
-            cd(testCase.h5Dir);
-            if isfile(testCase.h5Name)
+        function runBemioPY(testCase)
+            cd(testCase.h5DirPY);
+            if isfile(testCase.h5NamePY)
+                fprintf('runBemio skipped, *.h5 already exists\n')
+            else
+                bemio
+            end
+            cd(testCase.testDir)
+        end
+
+        function runBemioVM(testCase)
+            cd(testCase.h5DirVM);
+            if isfile(testCase.h5NameVM)
                 fprintf('runBemio skipped, *.h5 already exists\n')
             else
                 bemio
@@ -38,21 +50,30 @@ function runBemio(testCase)
         end
 
     end
+
+    methods(TestMethodTeardown)
+        function returnHome(testCase)
+            cd(testCase.testDir)
+        end
+    end
 
     methods(TestClassTeardown)
-        
         function checkVisibilityRestored(testCase)
             set(0, 'DefaultFigureVisible', testCase.OriginalDefault);
             testCase.assertEqual(get(0, 'DefaultFigureVisible'),    ...
                                  testCase.OriginalDefault);
-        end
-        
+        end 
     end
 
     methods(Test)
-        function testCable(testCase)
+        function testPY(testCase)
+            cd('Passive_Yaw')
             runCases
         end
+        function testVM(testCase)
+            cd('Variable_Mass')
+            wecSim
+        end
     end
 
 end

Variable_Hydro/Variable_Mass/README.md

@@ -0,0 +1,20 @@
+# Variable Hydrodynamics Variable Mass
+
+**Author:** Jeff Grasberger
+
+**Geometry:**	Sphere
+
+**Original Version:** 	WEC-Sim v6.1
+
+**Description**
+
+This application demonstrates using WEC-Sim's variable hydrodynamics feature to model a sphere with a variable mass and draft.
+The sphere's mass is set-up to change instantaneously every 100 seconds, increasing the its draft. 
+The existing model is simple but can be built upon to demonstrate any WEC that changes mass during a simulation.
+WEC-Sim by default does not support variable mass, so this model requires a broken library link to add the General Variable Mass block.
+To recreate (for future library updates): duplicate the changes within sphereVarMass/Float/Hydrodynamic Body/Structure
+R2021b or later is required because the Simulink model uses the "Create Diagonal Matrix" block which was only moved to standard Simulink in R2021b.
+
+**Relevant Citation(s)**
+
+Keester, A.; Ogden, D.; Husain, S.; Ruehl, K.; Pan, J.; Quiroga, J.; Grasberger, J.; Forbush, D.; Tom, N.; Housner, S.; Tran, T. (2023). Review of TEAMER Awards for WEC-Sim Support. Paper presented at 15th European Wave and Tidal Energy Conference (EWTEC 2023), Bilbao, Spain. https://doi.org/10.36688/ewtec-2023-261

Variable_Hydro/Variable_Mass/calcIndex.m

@@ -0,0 +1,9 @@
+function body1_hydroForceIndex = calcIndex(time)
+
+body1_hydroForceIndex = floor(time/100) + 1; % Increase the mass every 100 seconds
+
+if body1_hydroForceIndex > 9
+    body1_hydroForceIndex = 9; % restrict to 9 (# of hydrodata files)
+end
+
+end

Variable_Hydro/Variable_Mass/hydroData/bemio.m

@@ -0,0 +1,15 @@
+close all
+
+for ii = 1:9
+
+    hydro = struct();
+
+    outName = ['draft' num2str(ii) '.out'];
+
+    hydro = readWAMIT(hydro,outName,[]);
+    hydro = radiationIRF(hydro,15,[],[],[],6);
+    hydro = radiationIRFSS(hydro,[],[]);
+    hydro = excitationIRF(hydro,15,[],[],[],[]);
+    writeBEMIOH5(hydro)
+
+end