git.gag.com Git - debian/openrocket/blob - src/net/sf/openrocket/aerodynamics/AtmosphericModel.java

   1 package net.sf.openrocket.aerodynamics;
   2
   3 public abstract class AtmosphericModel {
   4         /** Layer thickness of interpolated altitude. */
   5         private static final double DELTA = 500;
   6
   7         private AtmosphericConditions[] levels = null;
   8
   9
  10         public AtmosphericConditions getConditions(double altitude) {
  11                 if (levels == null)
  12                         computeLayers();
  13
  14                 if (altitude <= 0)
  15                         return levels[0];
  16                 if (altitude >= DELTA*(levels.length-1))
  17                         return levels[levels.length-1];
  18
  19                 int n = (int)(altitude/DELTA);
  20                 double d = (altitude - n*DELTA)/DELTA;
  21                 AtmosphericConditions c = new AtmosphericConditions();
  22                 c.temperature = levels[n].temperature * (1-d) + levels[n+1].temperature * d;
  23                 c.pressure = levels[n].pressure * (1-d) + levels[n+1].pressure * d;
  24
  25                 return c;
  26         }
  27
  28
  29         private void computeLayers() {
  30                 double max = getMaxAltitude();
  31                 int n = (int)(max/DELTA) + 1;
  32                 levels = new AtmosphericConditions[n];
  33                 for (int i=0; i < n; i++) {
  34                         levels[i] = getExactConditions(i*DELTA);
  35                 }
  36         }
  37
  38
  39         public abstract double getMaxAltitude();
  40         public abstract AtmosphericConditions getExactConditions(double altitude);
  41 }