- Implemented a DampingMoment simulation listener example

[debian/openrocket] / core / src / net / sf / openrocket / simulation / listeners / example / DampingMoment.java

diff --git a/core/src/net/sf/openrocket/simulation/listeners/example/DampingMoment.java b/core/src/net/sf/openrocket/simulation/listeners/example/DampingMoment.java
new file mode 100644 (file)
index 0000000..b9d2e46
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+++ b/core/src/net/sf/openrocket/simulation/listeners/example/DampingMoment.java
@@ -0,0 +1,129 @@
+package net.sf.openrocket.simulation.listeners.example;
+
+import java.util.List;
+import java.util.Map;
+
+import net.sf.openrocket.aerodynamics.AerodynamicCalculator;
+import net.sf.openrocket.aerodynamics.AerodynamicForces;
+import net.sf.openrocket.aerodynamics.FlightConditions;
+import net.sf.openrocket.motor.MotorId;
+import net.sf.openrocket.motor.MotorInstance;
+import net.sf.openrocket.motor.MotorInstanceConfiguration;
+import net.sf.openrocket.rocketcomponent.MotorMount;
+import net.sf.openrocket.rocketcomponent.RocketComponent;
+import net.sf.openrocket.simulation.FlightDataBranch;
+import net.sf.openrocket.simulation.FlightDataType;
+import net.sf.openrocket.simulation.SimulationStatus;
+import net.sf.openrocket.simulation.exception.SimulationException;
+import net.sf.openrocket.simulation.listeners.AbstractSimulationListener;
+import net.sf.openrocket.unit.UnitGroup;
+import net.sf.openrocket.util.ArrayList;
+import net.sf.openrocket.util.Coordinate;
+import net.sf.openrocket.util.PolyInterpolator;
+
+public class DampingMoment extends AbstractSimulationListener {
+       
+       private static final FlightDataType type = FlightDataType.getType("Damping moment coefficient", "Cdm", UnitGroup.UNITS_COEFFICIENT);
+       private static final FlightDataType[] typeList = {type};
+       
+       public String getName(){
+               return "Damping moment listener";
+       }
+       
+       /**
+        * Return a list of any flight data types this listener creates.
+        */
+       public FlightDataType[] getFlightDataTypes(){
+               return typeList;
+       }
+       
+       @Override
+       public FlightConditions postFlightConditions(SimulationStatus status, FlightConditions flightConditions) throws SimulationException {
+               
+               // Save it as a flightdatatype
+               
+               //status.getFlightData().setValue(type, aerodynamicPart + propulsivePart);
+               status.getFlightData().setValue(type, calculate(status, flightConditions));
+
+               return flightConditions;
+       }
+       
+       private double calculate(SimulationStatus status, FlightConditions flightConditions){
+               
+               // Work out the propulsive/jet damping part of the moment.
+               
+               // dm/dt = (thrust - ma)/v
+               FlightDataBranch data = status.getFlightData();
+               
+               List<Double> mpAll = data.get(FlightDataType.TYPE_PROPELLANT_MASS);
+               List<Double> time = data.get(FlightDataType.TYPE_TIME);
+               if (mpAll == null || time == null){
+                       return Double.NaN;
+               }
+               
+               int len = mpAll.size();
+               
+               // This isn't as accurate as I would like
+               double mdot=Double.NaN;
+               if (len > 2){
+                       // Using polynomial interpolator for derivative. Doesn't help much
+                       //double[] x = { time.get(len-5), time.get(len-4), time.get(len-3), time.get(len-2), time.get(len-1) };
+                       //double[] y = { mpAll.get(len-5), mpAll.get(len-4), mpAll.get(len-3), mpAll.get(len-2), mpAll.get(len-1) };
+                       //PolyInterpolator interp = new PolyInterpolator(x);
+                       //double[] coeff = interp.interpolator(y);
+                       //double dt = .01;
+                       //mdot = (interp.eval(x[4], coeff) - interp.eval(x[4]-dt, coeff))/dt; 
+                                               
+                       mdot = (mpAll.get(len-1) - mpAll.get(len-2)) / (time.get(len-1) - time.get(len-2));
+               }
+               
+               double cg = data.getLast(FlightDataType.TYPE_CG_LOCATION);
+               
+               // find the maximum distance from nose to nozzle. 
+               double nozzleDistance = 0;
+               for (MotorId id: status.getMotorConfiguration().getMotorIDs()){
+                       MotorInstanceConfiguration config = status.getMotorConfiguration();
+                       Coordinate position = config.getMotorPosition(id);
+                       
+                       double x = position.x + config.getMotorInstance(id).getParentMotor().getLength();
+                       if (x > nozzleDistance){
+                               nozzleDistance = x;
+                       }                       
+               }
+               
+               // now can get the propulsive part
+               double propulsivePart = mdot * Math.pow(nozzleDistance - cg, 2);
+               
+               // Work out the aerodynamic part of the moment.
+               double aerodynamicPart = 0;
+               
+               AerodynamicCalculator aerocalc = status.getSimulationConditions().getAerodynamicCalculator();
+               
+               // Must go through each component ...
+               Map<RocketComponent, AerodynamicForces> forces = aerocalc.getForceAnalysis(status.getConfiguration(), flightConditions, null);
+               for (Map.Entry<RocketComponent, AerodynamicForces> entry : forces.entrySet()){
+                       
+                       RocketComponent comp = entry.getKey();
+                       
+                       if (!comp.isAerodynamic()) continue;
+                       
+                       //System.out.println(comp.toString());
+                       
+                       double CNa = entry.getValue().getCNa(); //?
+                       double Cp = entry.getValue().getCP().length();
+                       double z = comp.getPositionValue(); //?
+                       
+                       aerodynamicPart += CNa*Math.pow(z-Cp, 2);
+               }
+               
+               double v = flightConditions.getVelocity();
+               double rho = flightConditions.getAtmosphericConditions().getDensity();
+               double ar = flightConditions.getRefArea();
+               
+               aerodynamicPart = aerodynamicPart * .5 * rho * v * ar;
+               
+               return aerodynamicPart + propulsivePart;
+       
+       }
+       
+}