Added missing overloads for viscosity

Author: Erik Ovegard

UnitsNet.Tests/CustomCode/DensityTests.cs

@@ -58,5 +58,12 @@ public static void VolumeTimesDensityEqualsMass()
             Mass mass = Volume.FromCubicMeters(3)*Density.FromKilogramsPerCubicMeter(2);
             Assert.AreEqual(mass, Mass.FromKilograms(6));
         }
+
+        [Test]
+        public static void DensityTimesKinematicViscosityEqualsDynamicViscosity()
+        {
+            DynamicViscosity dynamicViscosity = Density.FromKilogramsPerCubicMeter(2) * KinematicViscosity.FromSquareMetersPerSecond(10);
+            Assert.AreEqual(dynamicViscosity, DynamicViscosity.FromNewtonSecondsPerMeterSquared(20));
+        }
     }
 }

UnitsNet.Tests/CustomCode/DynamicViscosityTests.cs

@@ -33,5 +33,11 @@ public class DynamicViscosityTests : DynamicViscosityTestsBase
         protected override double PascalSecondsInOneNewtonSecondPerMeterSquared => 1;
         protected override double PoiseInOneNewtonSecondPerMeterSquared => 10;
 
+        [Test]
+        public static void DynamicViscosityDividedByDensityEqualsKinematicViscosity()
+        {
+            KinematicViscosity kinematicViscosity = DynamicViscosity.FromNewtonSecondsPerMeterSquared(10) / Density.FromKilogramsPerCubicMeter(2);
+            Assert.AreEqual(kinematicViscosity, KinematicViscosity.FromSquareMetersPerSecond(5));
+        }
     }
 }

UnitsNet.Tests/CustomCode/KinematicViscosityTests.cs

@@ -76,5 +76,12 @@ public static void TimeSpanTimesKinematicViscosityEqualsArea()
             Area area = TimeSpan.FromSeconds(2)*KinematicViscosity.FromSquareMetersPerSecond(4);
             Assert.AreEqual(area, Area.FromSquareMeters(8));
         }
+
+        [Test]
+        public static void KinematicViscosityTimesDensityEqualsDynamicViscosity()
+        {
+            DynamicViscosity dynamicViscosity = KinematicViscosity.FromSquareMetersPerSecond(10) * Density.FromKilogramsPerCubicMeter(2);
+            Assert.AreEqual(dynamicViscosity, DynamicViscosity.FromNewtonSecondsPerMeterSquared(20));
+        }
     }
 }

UnitsNet/CustomCode/UnitClasses/Density.extra.cs

@@ -32,5 +32,10 @@ public partial struct Density
         {
             return Mass.FromKilograms(density.KilogramsPerCubicMeter*volume.CubicMeters);
         }
+
+        public static DynamicViscosity operator *(Density density, KinematicViscosity kinematicViscosity)
+        {
+            return DynamicViscosity.FromNewtonSecondsPerMeterSquared(kinematicViscosity.SquareMetersPerSecond * density.KilogramsPerCubicMeter);
+        }
     }
 }

UnitsNet/CustomCode/UnitClasses/DynamicViscosity.extra.cs

@@ -0,0 +1,33 @@
+// Copyright(c) 2007 Andreas Gullberg Larsen
+// https://github.com/anjdreas/UnitsNet
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+using System;
+
+namespace UnitsNet
+{
+    public partial struct DynamicViscosity
+    {
+        public static KinematicViscosity operator /(DynamicViscosity dynamicViscosity, Density density)
+        {
+            return KinematicViscosity.FromSquareMetersPerSecond(dynamicViscosity.NewtonSecondsPerMeterSquared / density.KilogramsPerCubicMeter);
+        }
+    }
+}

UnitsNet/CustomCode/UnitClasses/KinematicViscosity.extra.cs

@@ -49,5 +49,10 @@ public partial struct KinematicViscosity
         {
             return Area.FromSquareMeters(kinematicViscosity.SquareMetersPerSecond*duration.Seconds);
         }
+
+        public static DynamicViscosity operator *(KinematicViscosity kinematicViscosity, Density density)
+        {
+            return DynamicViscosity.FromNewtonSecondsPerMeterSquared(kinematicViscosity.SquareMetersPerSecond * density.KilogramsPerCubicMeter);
+        }
     }
 }