From 1a7a489c7ed061d117000c13893a172083b06505 Mon Sep 17 00:00:00 2001
From: Will Bainbridge <http://cfd.direct>
Date: Mon, 12 Feb 2018 09:08:52 +0000
Subject: [PATCH] InjectionModel: Removed the limit on the number of particles
 per parcel

A lower limit of one on the number of particles represented by a single
parcel has been removed from the injection models. It may be appropriate
to simulate the statistical behaviour of a particulate flow with more
lagrangian elements than physical particles. A unity lower limit does
not permit this.

The limit was, in some situations, also causing the large-diameter end
of an injected distribution to be clipped.

This resolves bug report https://bugs.openfoam.org/view.php?id=2837
---
 .../InjectionModel/InjectionModel.C           | 34 ++++++-------------
 .../InjectionModel/InjectionModel.H           |  6 +---
 2 files changed, 11 insertions(+), 29 deletions(-)

diff --git a/src/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectionModel/InjectionModel.C b/src/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectionModel/InjectionModel.C
index 434fd37b5..7d1846640 100644
--- a/src/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectionModel/InjectionModel.C
+++ b/src/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectionModel/InjectionModel.C
@@ -198,7 +198,7 @@ Foam::scalar Foam::InjectionModel<CloudType>::setNumberOfParticles
             scalar volumep = pi/6.0*pow3(diameter);
             scalar volumeTot = massTotal_/rho;
 
-            nP = (volumeFraction*volumeTot + delayedVolume_)/(parcels*volumep);
+            nP = volumeFraction*volumeTot/(parcels*volumep);
             break;
         }
         case pbNumber:
@@ -274,8 +274,7 @@ Foam::InjectionModel<CloudType>::InjectionModel(CloudType& owner)
     parcelBasis_(pbNumber),
     nParticleFixed_(0.0),
     time0_(0.0),
-    timeStep0_(this->template getModelProperty<scalar>("timeStep0")),
-    delayedVolume_(0.0)
+    timeStep0_(this->template getModelProperty<scalar>("timeStep0"))
 {}
 
 
@@ -302,8 +301,7 @@ Foam::InjectionModel<CloudType>::InjectionModel
     parcelBasis_(pbNumber),
     nParticleFixed_(0.0),
     time0_(owner.db().time().value()),
-    timeStep0_(this->template getModelProperty<scalar>("timeStep0")),
-    delayedVolume_(0.0)
+    timeStep0_(this->template getModelProperty<scalar>("timeStep0"))
 {
     // Provide some info
     // - also serves to initialise mesh dimensions - needed for parallel runs
@@ -369,8 +367,7 @@ Foam::InjectionModel<CloudType>::InjectionModel
     parcelBasis_(im.parcelBasis_),
     nParticleFixed_(im.nParticleFixed_),
     time0_(im.time0_),
-    timeStep0_(im.timeStep0_),
-    delayedVolume_(im.delayedVolume_)
+    timeStep0_(im.timeStep0_)
 {}
 
 
@@ -428,8 +425,6 @@ void Foam::InjectionModel<CloudType>::inject
 
     if (prepareForNextTimeStep(time, newParcels, newVolumeFraction))
     {
-        scalar delayedVolume = 0;
-
         const scalar trackTime = this->owner().solution().trackTime();
         const polyMesh& mesh = this->owner().mesh();
 
@@ -505,30 +500,21 @@ void Foam::InjectionModel<CloudType>::inject
                             pPtr->rho()
                         );
 
-                    if (pPtr->nParticle() >= 1.0)
-                    {
-                        parcelsAdded++;
-                        massAdded += pPtr->nParticle()*pPtr->mass();
+                    parcelsAdded ++;
 
-                        if (pPtr->move(cloud, td, dt))
-                        {
-                            cloud.addParticle(pPtr);
-                        }
-                        else
-                        {
-                            delete pPtr;
-                        }
+                    massAdded += pPtr->nParticle()*pPtr->mass();
+
+                    if (pPtr->move(cloud, td, dt))
+                    {
+                        cloud.addParticle(pPtr);
                     }
                     else
                     {
-                        delayedVolume += pPtr->nParticle()*pPtr->volume();
                         delete pPtr;
                     }
                 }
             }
         }
-
-        delayedVolume_ = delayedVolume;
     }
 
     postInjectCheck(parcelsAdded, massAdded);
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectionModel/InjectionModel.H b/src/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectionModel/InjectionModel.H
index 5ee312f2c..c8aefcda1 100644
--- a/src/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectionModel/InjectionModel.H
+++ b/src/lagrangian/intermediate/submodels/Kinematic/InjectionModel/InjectionModel/InjectionModel.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2018 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -134,10 +134,6 @@ protected:
             //- Time at start of injection time step [s]
             scalar timeStep0_;
 
-            //- Volume that should have been injected, but would lead to
-            //  less than 1 particle per parcel
-            scalar delayedVolume_;
-
 
     // Protected Member Functions