Changeset 4889

Timestamp:

Dec 17, 2007, 5:20:12 PM (17 years ago)

Author:

sexton

Message:

green's law function (describes wave height approximation based on ratio of depths and wave height at one of those depths)

Location:

anuga_core/source/anuga/abstract_2d_finite_volumes

Files:

• test_util.py (modified) (2 diffs)
• util.py (modified) (1 diff)

anuga_core/source/anuga/abstract_2d_finite_volumes/test_util.py

@@ -1311 +1311 @@
         assert min1==1 
         assert max1==9
-
+        
     def test_get_min_max_values1(self):
         
@@ -1625 +1625 @@
         os.remove(point1_filename)
         os.remove(point2_filename)
-        
+
+    def test_greens_law(self):
+
+        from math import sqrt
+        
+        d1 = 80.0
+        d2 = 20.0
+        h1 = 1.0
+        h2 = greens_law(d1,d2,h1)
+
+        assert h2==sqrt(2.0)
+       
+
 #-------------------------------------------------------------
 if __name__ == "__main__":

anuga_core/source/anuga/abstract_2d_finite_volumes/util.py

@@ -2453 +2453 @@
         
 
-
-            
-
-    
-        
+def greens_law(d1,d2,h1,verbose=False):
+    """
+
+    Green's Law allows an approximation of wave amplitude at
+    a given depth based on the fourh root of the ratio of two depths
+    and the amplitude at another given depth.
+
+    Note, wave amplitude is equal to stage.
+    
+    Inputs:
+
+    d1, d2 - the two depths
+    h1     - the wave amplitude at d1
+    h2     - the derived amplitude at d2
+
+    h2 = h1 (d1/d2)^(1/4), where d2 cannot equal 0.
+    
+    """
+
+    d1 = ensure_numeric(d1)
+    d2 = ensure_numeric(d2)
+    h1 = ensure_numeric(h1)
+
+    if d1 <= 0.0:
+        msg = 'the first depth, d1 (%f), must be strictly positive' %(d1)
+        raise Exception(msg)
+
+    if d2 <= 0.0:
+        msg = 'the second depth, d2 (%f), must be strictly positive' %(d2)
+        raise Exception(msg)
+    
+    if h1 <= 0.0:
+        msg = 'the wave amplitude, h1 (%f), must be strictly positive' %(h1)
+        raise Exception(msg)
+    
+    h2 = h1*(d1/d2)**0.25
+
+    assert h2 > 0
+    
+    return h2
+