git.gag.com Git - debian/openrocket/blob - core/src/net/sf/openrocket/simulation/listeners/example/DampingMoment.java

   1 package net.sf.openrocket.simulation.listeners.example;
   2
   3 import java.util.List;
   4 import java.util.Map;
   5
   6 import net.sf.openrocket.aerodynamics.AerodynamicCalculator;
   7 import net.sf.openrocket.aerodynamics.AerodynamicForces;
   8 import net.sf.openrocket.aerodynamics.FlightConditions;
   9 import net.sf.openrocket.motor.MotorId;
  10 import net.sf.openrocket.motor.MotorInstance;
  11 import net.sf.openrocket.motor.MotorInstanceConfiguration;
  12 import net.sf.openrocket.rocketcomponent.MotorMount;
  13 import net.sf.openrocket.rocketcomponent.RocketComponent;
  14 import net.sf.openrocket.simulation.FlightDataBranch;
  15 import net.sf.openrocket.simulation.FlightDataType;
  16 import net.sf.openrocket.simulation.SimulationStatus;
  17 import net.sf.openrocket.simulation.exception.SimulationException;
  18 import net.sf.openrocket.simulation.listeners.AbstractSimulationListener;
  19 import net.sf.openrocket.unit.UnitGroup;
  20 import net.sf.openrocket.util.ArrayList;
  21 import net.sf.openrocket.util.Coordinate;
  22 import net.sf.openrocket.util.PolyInterpolator;
  23
  24 public class DampingMoment extends AbstractSimulationListener {
  25
  26         private static final FlightDataType type = FlightDataType.getType("Damping moment coefficient", "Cdm", UnitGroup.UNITS_COEFFICIENT);
  27         private static final FlightDataType[] typeList = {type};
  28
  29         public String getName(){
  30                 return "Damping moment listener";
  31         }
  32
  33         /**
  34          * Return a list of any flight data types this listener creates.
  35          */
  36         public FlightDataType[] getFlightDataTypes(){
  37                 return typeList;
  38         }
  39
  40         @Override
  41         public FlightConditions postFlightConditions(SimulationStatus status, FlightConditions flightConditions) throws SimulationException {
  42
  43                 // Save it as a flightdatatype
  44
  45                 //status.getFlightData().setValue(type, aerodynamicPart + propulsivePart);
  46                 status.getFlightData().setValue(type, calculate(status, flightConditions));
  47
  48                 return flightConditions;
  49         }
  50
  51         private double calculate(SimulationStatus status, FlightConditions flightConditions){
  52
  53                 // Work out the propulsive/jet damping part of the moment.
  54
  55                 // dm/dt = (thrust - ma)/v
  56                 FlightDataBranch data = status.getFlightData();
  57
  58                 List<Double> mpAll = data.get(FlightDataType.TYPE_PROPELLANT_MASS);
  59                 List<Double> time = data.get(FlightDataType.TYPE_TIME);
  60                 if (mpAll == null || time == null){
  61                         return Double.NaN;
  62                 }
  63
  64                 int len = mpAll.size();
  65
  66                 // This isn't as accurate as I would like
  67                 double mdot=Double.NaN;
  68                 if (len > 2){
  69                         // Using polynomial interpolator for derivative. Doesn't help much
  70                         //double[] x = { time.get(len-5), time.get(len-4), time.get(len-3), time.get(len-2), time.get(len-1) };
  71                         //double[] y = { mpAll.get(len-5), mpAll.get(len-4), mpAll.get(len-3), mpAll.get(len-2), mpAll.get(len-1) };
  72                         //PolyInterpolator interp = new PolyInterpolator(x);
  73                         //double[] coeff = interp.interpolator(y);
  74                         //double dt = .01;
  75                         //mdot = (interp.eval(x[4], coeff) - interp.eval(x[4]-dt, coeff))/dt;
  76
  77                         mdot = (mpAll.get(len-1) - mpAll.get(len-2)) / (time.get(len-1) - time.get(len-2));
  78                 }
  79
  80                 double cg = data.getLast(FlightDataType.TYPE_CG_LOCATION);
  81
  82                 // find the maximum distance from nose to nozzle.
  83                 double nozzleDistance = 0;
  84                 for (MotorId id: status.getMotorConfiguration().getMotorIDs()){
  85                         MotorInstanceConfiguration config = status.getMotorConfiguration();
  86                         Coordinate position = config.getMotorPosition(id);
  87
  88                         double x = position.x + config.getMotorInstance(id).getParentMotor().getLength();
  89                         if (x > nozzleDistance){
  90                                 nozzleDistance = x;
  91                         }
  92                 }
  93
  94                 // now can get the propulsive part
  95                 double propulsivePart = mdot * Math.pow(nozzleDistance - cg, 2);
  96
  97                 // Work out the aerodynamic part of the moment.
  98                 double aerodynamicPart = 0;
  99
 100                 AerodynamicCalculator aerocalc = status.getSimulationConditions().getAerodynamicCalculator();
 101
 102                 // Must go through each component ...
 103                 Map<RocketComponent, AerodynamicForces> forces = aerocalc.getForceAnalysis(status.getConfiguration(), flightConditions, null);
 104                 for (Map.Entry<RocketComponent, AerodynamicForces> entry : forces.entrySet()){
 105
 106                         RocketComponent comp = entry.getKey();
 107
 108                         if (!comp.isAerodynamic()) continue;
 109
 110                         //System.out.println(comp.toString());
 111
 112                         double CNa = entry.getValue().getCNa(); //?
 113                         double Cp = entry.getValue().getCP().length();
 114                         double z = comp.getPositionValue(); //?
 115
 116                         aerodynamicPart += CNa*Math.pow(z-Cp, 2);
 117                 }
 118
 119                 double v = flightConditions.getVelocity();
 120                 double rho = flightConditions.getAtmosphericConditions().getDensity();
 121                 double ar = flightConditions.getRefArea();
 122
 123                 aerodynamicPart = aerodynamicPart * .5 * rho * v * ar;
 124
 125                 return aerodynamicPart + propulsivePart;
 126
 127         }
 128
 129 }