/// <summary>
/// This is the timestepping procedure
/// </summary>
/// <param name="TimeStep"></param>
public void Update(DateTime NewTime)
{
CurrentTimeStep = NewTime.Subtract(CurrentTime);
#region Sum of Sinks and sources
//Sum the sources
var GWFlow = GroundwaterBoundaries.Where(var => var.IsSource(CurrentTime)).Select(var => var.GetSourceWater(CurrentTime, CurrentTimeStep));
var SourceFlow = Sources.Select(var => var.GetSourceWater(CurrentTime, CurrentTimeStep));
IWaterPacket InFlow = WaterMixer.Mix(GWFlow.Concat(SourceFlow));
double InflowVolume = 0;
if (InFlow != null)
{
InflowVolume = InFlow.Volume;
}
//Sum the Evaporation boundaries
double EvapoVolume = _evapoBoundaries.Sum(var => var.GetSinkVolume(CurrentTime, CurrentTimeStep));
//Sum the sinks
double SinkVolume = Sinks.Sum(var => var.GetSinkVolume(CurrentTime, CurrentTimeStep));
//Add the sinking groundwater boundaries
SinkVolume += GroundwaterBoundaries.Where(var => !var.IsSource(CurrentTime)).Sum(var => var.GetSinkVolume(CurrentTime, CurrentTimeStep));
double sumSinkSources = InflowVolume - EvapoVolume - SinkVolume;
//If we have no water from upstream but Inflow, remove water from inflow to fill stream
if (sumSinkSources / Volume > 5)
{
AddWaterPacket(CurrentTime, NewTime, InFlow.Substract(sumSinkSources - Volume * 5));
InflowVolume = InFlow.Volume;
sumSinkSources = InflowVolume - EvapoVolume - SinkVolume;
}
//Sort the incoming water an put in to queue
PrePareIncomingWater();
//Calculate the surplus
WaterToRoute = _waterInStream.Sum(var => var.Volume) + InflowVolume - EvapoVolume - SinkVolume - Volume + _incomingWater.Sum(var => var.Volume);
//If the loss is bigger than available water, reduce Evaporation and Sinks
if (WaterToRoute + Volume < 0)
{
double reductionfactor = 1 + (WaterToRoute + Volume) / (EvapoVolume + SinkVolume);
EvapoVolume *= reductionfactor;
SinkVolume *= reductionfactor;
WaterToRoute = 0;
}
//Convert to rates
double qu = sumSinkSources / CurrentTimeStep.TotalSeconds / Volume;
double qop = _incomingWater.Sum(var => var.Volume) / CurrentTimeStep.TotalSeconds;
double qout = qu * Volume + qop;
//Create a mixer class
Mixer M = new Mixer(InFlow, EvapoVolume, SinkVolume);
#endregion
#region Stored water
//Send stored water out
if (WaterToRoute > 0)
{
double OutflowTime = 0;
//The volume that needs to flow out to meet the watertotroute
double VToSend = WaterToRoute;
if (qu != 0)
{
VToSend = qout / qu * (1 - 1 / (Math.Exp(qu * CurrentTimeStep.TotalSeconds)));
}
//There is water in the stream that should be routed
while (VToSend > 0 & _waterInStream.Count > 0)
{
IWaterPacket IW;
//Mixing during flow towards end of stream
double dv = _waterInStream.Peek().Volume *(Math.Exp(qu * OutflowTime) - 1);
//Check if the entire water packet should flow out or it should be split
if (_waterInStream.Peek().Volume + dv < VToSend)
{
IW = _waterInStream.Dequeue();
}
else
{
IW = _waterInStream.Peek().Substract(VToSend);
}
//Update how mush water is yet to be routed
VToSend -= IW.Volume;
//Now do the mix
M.Mix(dv, IW);
//Calculate outflow time
double dt;
if (qu == 0)
{
dt = IW.Volume / qop;
}
else
{
dt = Math.Log(qout / (qout - qu * IW.Volume)) / qu;
}
//Mixing during outflow
M.Mix(qout * dt - IW.Volume, IW);
IW.MoveInTime(TimeSpan.FromSeconds(OutflowTime + dt / 2), IW.Volume / Depth);
SendWaterDownstream(IW);
OutflowTime += dt;
}
}
//Now move the remaining packets to their final destination and time
foreach (IWaterPacket IWP in _waterInStream)
{
if (qu != 0)
{
M.Mix(IWP.Volume * (Math.Exp(qu * CurrentTimeStep.TotalSeconds) - 1), IWP);
}
IWP.MoveInTime(CurrentTimeStep, IWP.Volume / Depth);
}
#endregion
#region Water packets traveling right through
double inflowtime = 0;
//No water in stream and incoming water. Just pass through
if (_waterInStream.Count == 0 & _incomingWater.Count > 0)
{
//Calculate how much incoming water is required to fill stream volume;
double VToStore = Volume;
if (qu != 0)
{
VToStore = qop / qu * Math.Log(Volume * qu / qop + 1);
}
//Now send water through
double incomingVolume = _incomingWater.Sum(var => var.Volume);
//Send packets through until the remaining will just fill the stream
while (incomingVolume > VToStore + 1e-12 & _incomingWater.Count != 0)
{
IWaterPacket WP;
if (incomingVolume - _incomingWater.Peek().Volume > VToStore)
{
WP = _incomingWater.Dequeue();
}
else
{
WP = _incomingWater.Peek().Substract(incomingVolume - VToStore);
}
incomingVolume -= WP.Volume;
//Keep track of inflow time.
inflowtime += WP.Volume / qop;
if (qu != 0)
{
double dvr = WP.Volume * qu * Volume / qop;
M.Mix(dvr, WP);
}
//Calculate the time a water package uses to travel through the stream
TimeSpan CurrentTravelTime;
if (qu != 0)
{
CurrentTravelTime = TimeSpan.FromSeconds(1 / qu * Math.Log(Volume * qu / qop + 1));
}
else
{
CurrentTravelTime = TimeSpan.FromSeconds(Volume / qout);
}
//Moves right through
WP.MoveInTime(CurrentTravelTime, WP.Volume / Depth);
SendWaterDownstream(WP);
}
}
#endregion
#region Fill the stream
//The remaining incoming water is moved forward and stays in the stream.
while (_incomingWater.Count > 0)
{
IWaterPacket WP = _incomingWater.Dequeue();
double dt = WP.Volume / qop;
inflowtime += dt;
double dt2 = CurrentTimeStep.TotalSeconds - inflowtime; //How much of the timestep is left when this packet has moved in.
if (qu != 0)
{
//Volume change during inflow
double Vnew = qop * (Math.Exp(qu * dt) - 1) / qu;
//Volume change while in stream
Vnew *= Math.Exp(qu * dt2);
M.Mix(Vnew - WP.Volume, WP);
}
//The time is half the inflowtime + the time in stream
WP.MoveInTime(TimeSpan.FromSeconds(dt2 + dt / 2), WP.Volume / Depth);
_waterInStream.Enqueue(WP);
}
#endregion
Output.Outflow.AddSiValue(CurrentTime, NewTime, WaterToRoute / CurrentTimeStep.TotalSeconds);
CurrentTime = NewTime;
StartofFlowperiod = CurrentTime;
}