rotorDiskSource: Added output of rotor power

Patch contributed by Robert Lee
Resolves patch request https://bugs.openfoam.org/view.php?id=3262

Author: Henry Weller

src/fvOptions/sources/derived/rotorDiskSource/rotorDiskSource.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2018 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2019 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -384,7 +384,7 @@ void Foam::fv::rotorDiskSource::createCoordinateSystem()
 
     const scalar sumArea = gSum(area_);
     const scalar diameter = Foam::sqrt(4.0*sumArea/mathematical::pi);
-    Info<< "    Rotor gometry:" << nl
+    Info<< "    Rotor geometry:" << nl
         << "    - disk diameter = " << diameter << nl
         << "    - disk area     = " << sumArea << nl
         << "    - origin        = " << coordSys_.origin() << nl

src/fvOptions/sources/derived/rotorDiskSource/rotorDiskSourceTemplates.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2018 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2019 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -49,6 +49,7 @@ void Foam::fv::rotorDiskSource::calculate
     scalar liftEff = 0.0;
     scalar AOAmin = great;
     scalar AOAmax = -great;
+    scalar powerEff = 0.0;
 
     forAll(cells_, i)
     {
@@ -127,6 +128,7 @@ void Foam::fv::rotorDiskSource::calculate
             // Accumulate forces
             dragEff += rhoRef_*localForce.y();
             liftEff += rhoRef_*localForce.z();
+            powerEff += rhoRef_ * localForce.y() * radius * omega_;
 
             // Transform force from local coning system into rotor cylindrical
             localForce = invR_[i] & localForce;
@@ -151,6 +153,7 @@ void Foam::fv::rotorDiskSource::calculate
         Info<< type() << " output:" << nl
             << "    min/max(AOA)   = " << radToDeg(AOAmin) << ", "
             << radToDeg(AOAmax) << nl
+            << "    Effective power = " << powerEff << nl
             << "    Effective drag = " << dragEff << nl
             << "    Effective lift = " << liftEff << endl;
     }