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[fixes #387] Increases accuracy of Center-Of-Pressure calculations on instanced assemblies

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Daniel_M_Williams 2019-01-02 16:49:44 -05:00
parent 055132aa99
commit eed5863790
3 changed files with 11 additions and 10 deletions
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3
core/src/net/sf/openrocket/aerodynamics/AerodynamicForces.java
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@ -411,6 +411,9 @@ public class AerodynamicForces implements Cloneable, Monitorable {
public AerodynamicForces multiplex(final int instanceCount) {
this.cp = cp.setWeight(cp.weight*instanceCount);
if(1 < instanceCount) {
this.cp = cp.setY(0f).setZ(0f);
}
this.CNa = CNa*instanceCount;
this.CN = CN*instanceCount;
this.Cm = Cm*instanceCount;

11
core/src/net/sf/openrocket/aerodynamics/BarrowmanCalculator.java
View File

@ -207,7 +207,7 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
Coordinate cp_weighted = cp_comp.setWeight(cp_comp.weight);
Coordinate cp_absolute = component.toAbsolute(cp_weighted)[0];
if(1 < component.getInstanceCount()) {
cp_absolute = cp_absolute.setY(0.);
cp_absolute = cp_absolute.setY(0.).setZ(0.);
}
componentForces.setCP(cp_absolute);
@ -215,19 +215,18 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
componentForces.setCm(CN_instanced * componentForces.getCP().x / conditions.getRefLength());
// if( 0.0001 < Math.abs(componentForces.getCNa())){
// System.err.println(String.format("%s....Component.CNa: %g @ CP: %g, %g", indent, componentForces.getCNa(), componentForces.getCP().x, componentForces.getCP().y));
// final Coordinate cp = assemblyForces.getCP();
// System.err.println(String.format("%s....Component.CNa: %g @ CP: { %f, %f, %f}", indent, componentForces.getCNa(), cp.x, cp.y, cp.z));
// }
assemblyForces.merge(componentForces);
}
// if( 0.0001 < Math.abs(0 - assemblyForces.getCNa())){
// System.err.println(String.format("%s....Assembly.CNa: %g @ CPx: %g", indent, assemblyForces.getCNa(), assemblyForces.getCP().x));
// final Coordinate cp = assemblyForces.getCP();
// System.err.println(String.format("%s....Assembly.CNa: %g @ CP: { %f, %f, %f}", indent, assemblyForces.getCNa(), cp.x, cp.y, cp.z));
// }
// fetches instanced versions
// int instanceCount = component.getLocations().length;
if( component.allowsChildren() && (component.getInstanceCount() > 1)) {
return assemblyForces.multiplex(component.getInstanceCount());
}else {

7
core/test/net/sf/openrocket/aerodynamics/BarrowmanCalculatorTest.java
View File

@ -97,7 +97,6 @@ public class BarrowmanCalculatorTest {
FlightConditions conditions = new FlightConditions(config);
WarningSet warnings = new WarningSet();
// calculated from OpenRocket 15.03:
//double expCPx = 0.225;
// verified from the equations:
@ -110,7 +109,7 @@ public class BarrowmanCalculatorTest {
}
@Test
public void testCPDoubleStrapOn() {
public void testCPParallelBoosters() {
final Rocket rocket = TestRockets.makeFalcon9Heavy();
final ParallelStage boosterStage = (ParallelStage) rocket.getChild(1).getChild(0).getChild(0);
final TrapezoidFinSet boosterFins = (TrapezoidFinSet) boosterStage.getChild(1).getChild(1);
@ -138,8 +137,8 @@ public class BarrowmanCalculatorTest {
final Coordinate cp_1fin = calc.getCP(config, conditions, warnings);
assertEquals(" Falcon 9 Heavy CNa value is incorrect:", 9.36306412, cp_1fin.weight, EPSILON);
assertEquals(" Falcon 9 Heavy CP x value is incorrect:", 0.87521867, cp_1fin.x, EPSILON);
assertEquals(" Falcon 9 Heavy CP y value is incorrect:", 0.08564455, cp_1fin.y, EPSILON);
assertEquals(" Falcon 9 Heavy CP z value is incorrect:", 0.01766062, cp_1fin.z, EPSILON);
assertEquals(" Falcon 9 Heavy CP y value is incorrect:", 0f, cp_1fin.y, EPSILON);
assertEquals(" Falcon 9 Heavy CP z value is incorrect:", 0f, cp_1fin.z, EPSILON);
}{
// absent -- 3.28901627g @[0.31469937,0.05133333,0.00000000]
}