git.gag.com Git - debian/openrocket/blob - core/src/net/sf/openrocket/aerodynamics/barrowman/LaunchLugCalc.java

   1 package net.sf.openrocket.aerodynamics.barrowman;
   2
   3 import net.sf.openrocket.aerodynamics.AerodynamicForces;
   4 import net.sf.openrocket.aerodynamics.FlightConditions;
   5 import net.sf.openrocket.aerodynamics.WarningSet;
   6 import net.sf.openrocket.rocketcomponent.LaunchLug;
   7 import net.sf.openrocket.rocketcomponent.RocketComponent;
   8 import net.sf.openrocket.util.MathUtil;
   9
  10 public class LaunchLugCalc extends RocketComponentCalc {
  11
  12         private double CDmul;
  13         private double refArea;
  14
  15         public LaunchLugCalc(RocketComponent component) {
  16                 super(component);
  17
  18                 LaunchLug lug = (LaunchLug)component;
  19                 double ld = lug.getLength() / (2*lug.getOuterRadius());
  20
  21                 CDmul = Math.max(1.3 - ld, 1);
  22                 refArea = Math.PI * MathUtil.pow2(lug.getOuterRadius()) -
  23                                   Math.PI * MathUtil.pow2(lug.getInnerRadius()) * Math.max(1 - ld, 0);
  24         }
  25
  26         @Override
  27         public void calculateNonaxialForces(FlightConditions conditions,
  28                         AerodynamicForces forces, WarningSet warnings) {
  29                 // Nothing to be done
  30         }
  31
  32         @Override
  33         public double calculatePressureDragForce(FlightConditions conditions,
  34                         double stagnationCD, double baseCD, WarningSet warnings) {
  35
  36                 return CDmul*stagnationCD * refArea / conditions.getRefArea();
  37         }
  38
  39 }