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Merge pull request #601 from teyrana/fix/600/split-fins-cp

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[Request Review] Corrects the cp calculations for Split-fin rockets.  Fixes #600.
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Daniel Williams 2020-04-05 20:54:31 -04:00 committed by GitHub
commit 58eb9fff90
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4 changed files with 155 additions and 56 deletions
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17
core/src/net/sf/openrocket/aerodynamics/BarrowmanCalculator.java
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@ -183,6 +183,8 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
final AerodynamicForces assemblyForces= new AerodynamicForces().zero();
// System.err.println("======================================");
// System.err.println("==== Iterating through components ====");
// iterate through all components
for(Map.Entry<RocketComponent, ArrayList<InstanceContext>> entry: imap.entrySet() ) {
final RocketComponent comp = entry.getKey();
@ -195,24 +197,31 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
for(InstanceContext context: contextList ) {
AerodynamicForces instanceForces = new AerodynamicForces().zero();
// System.err.println(String.format("@ [%s]:[%d/%d]", comp.getName(), context.instanceNumber + 1, comp.getInstanceCount()));
// System.err.println("_________ inst/ctxt: xrotation: " + context.transform.getXrotation());
calcObj.calculateNonaxialForces(conditions, context.transform, instanceForces, warnings);
Coordinate cp_comp = instanceForces.getCP();
Coordinate cp_abs = context.transform.transform(cp_comp);
Coordinate cp_inst = instanceForces.getCP();
Coordinate cp_abs = context.transform.transform(cp_inst);
if ((comp instanceof FinSet) && (((FinSet)comp).getFinCount() > 2))
cp_abs = cp_abs.setY(0.0).setZ(0.0);
// if( 1e-6 < cp_inst.weight) {
// System.err.println("_________ cp:inst: (rel): " + cp_inst.toString());
// System.err.println("_________ cp:inst: (abs): " + cp_abs.toString());
// }
instanceForces.setCP(cp_abs);
double CN_instanced = instanceForces.getCN();
instanceForces.setCm(CN_instanced * instanceForces.getCP().x / conditions.getRefLength());
// System.err.println("instanceForces=" + instanceForces);
assemblyForces.merge(instanceForces);
}
}
}
// System.err.println("assemblyForces=" + assemblyForces);
// System.err.println("____ cp:asbly: " + assemblyForces.getCP().toString());
return assemblyForces;
}

7
core/src/net/sf/openrocket/aerodynamics/barrowman/FinSetCalc.java
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@ -49,7 +49,6 @@ public class FinSetCalc extends RocketComponentCalc {
private final double thickness;
private final double bodyRadius;
private final int finCount;
private final double baseRotation;
private final double cantAngle;
private final FinSet.CrossSection crossSection;
@ -68,7 +67,6 @@ public class FinSetCalc extends RocketComponentCalc {
bodyRadius = fin.getBodyRadius();
finCount = fin.getFinCount();
baseRotation = fin.getBaseRotation();
cantAngle = fin.getCantAngle();
span = fin.getSpan();
finArea = fin.getPlanformArea();
@ -114,10 +112,12 @@ public class FinSetCalc extends RocketComponentCalc {
// Multiple fins with fin-fin interference
double cna;
double theta = conditions.getTheta();
double angle = baseRotation + transform.getXrotation();
double angle = transform.getXrotation();
// Compute basic CNa without interference effects
cna = cna1 * MathUtil.pow2(Math.sin(theta - angle));
// final double cna_x = cna1 * MathUtil.pow2(Math.sin(theta - angle));
// final double cna_y = cna1 * MathUtil.pow2(Math.sin(theta - angle));
// logger.debug("Component cna = {}", cna);
@ -166,7 +166,6 @@ public class FinSetCalc extends RocketComponentCalc {
// (Barrowman thesis pdf-page 40)
// TODO: LOW: fin-fin mach cone effect, MIL-HDBK page 5-25
// Calculate CP position
double x = macLead + calculateCPPos(conditions) * macLength;
// logger.debug("Component macLead = {}", macLead);

88
core/src/net/sf/openrocket/util/TestRockets.java
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@ -28,6 +28,7 @@ import net.sf.openrocket.rocketcomponent.CenteringRing;
import net.sf.openrocket.rocketcomponent.ClusterConfiguration;
import net.sf.openrocket.rocketcomponent.DeploymentConfiguration;
import net.sf.openrocket.rocketcomponent.DeploymentConfiguration.DeployEvent;
import net.sf.openrocket.rocketcomponent.EllipticalFinSet;
import net.sf.openrocket.rocketcomponent.EngineBlock;
import net.sf.openrocket.rocketcomponent.ExternalComponent;
import net.sf.openrocket.rocketcomponent.ExternalComponent.Finish;
@ -66,6 +67,12 @@ import net.sf.openrocket.startup.Application;
public class TestRockets {
public final static FlightConfigurationId TEST_FCID_0 = new FlightConfigurationId("d010716e-ce0e-469d-ae46-190f3653ebbf");
public final static FlightConfigurationId TEST_FCID_1 = new FlightConfigurationId("f41bee5b-ebb8-4d92-bce7-53001577a313");
public final static FlightConfigurationId TEST_FCID_2 = new FlightConfigurationId("3e8d1280-53c2-4234-89a7-de215ef5cd69");
public final static FlightConfigurationId TEST_FCID_3 = new FlightConfigurationId("415a5485-f2da-4c2a-8803-394220ae58b8");
public final static FlightConfigurationId TEST_FCID_4 = new FlightConfigurationId("5abc18ec-a200-46f1-90c4-60b6995fc933");
private final String key;
private final Random rnd;
@ -377,14 +384,6 @@ public class TestRockets {
return values[rnd.nextInt(values.length)];
}
final static FlightConfigurationId ESTES_ALPHA_III_FCID[] = {
null, // treat the array as 1-indexed.
new FlightConfigurationId("test_config #1: A8-0"),
new FlightConfigurationId("test_config #2: B4-3"),
new FlightConfigurationId("test_config #3: C6-3"),
new FlightConfigurationId("test_config #4: C6-5"),
new FlightConfigurationId("test_config #5: C6-7"),
};
// This is a Estes Alpha III
// http://www.rocketreviews.com/alpha-iii---estes-221256.html
@ -392,13 +391,12 @@ public class TestRockets {
// This function is used for unit, integration tests, DO NOT CHANGE (without updating tests).
public static final Rocket makeEstesAlphaIII(){
Rocket rocket = new Rocket();
FlightConfigurationId fcid[] = new FlightConfigurationId[5];
fcid[0] = rocket.createFlightConfiguration( ESTES_ALPHA_III_FCID[1] );
fcid[1] = rocket.createFlightConfiguration( ESTES_ALPHA_III_FCID[2] );
fcid[2] = rocket.createFlightConfiguration( ESTES_ALPHA_III_FCID[3] );
fcid[3] = rocket.createFlightConfiguration( ESTES_ALPHA_III_FCID[4] );
fcid[4] = rocket.createFlightConfiguration( ESTES_ALPHA_III_FCID[5] );
rocket.createFlightConfiguration( TEST_FCID_0 );
rocket.createFlightConfiguration( TEST_FCID_1 );
rocket.createFlightConfiguration( TEST_FCID_2 );
rocket.createFlightConfiguration( TEST_FCID_3 );
rocket.createFlightConfiguration( TEST_FCID_4 );
rocket.setName("Estes Alpha III / Code Verification Rocket");
AxialStage stage = new AxialStage();
@ -465,39 +463,39 @@ public class TestRockets {
inner.setMotorMount( true);
{
MotorConfiguration motorConfig = new MotorConfiguration(inner,fcid[0]);
MotorConfiguration motorConfig = new MotorConfiguration(inner, TEST_FCID_0);
Motor mtr = TestRockets.generateMotor_A8_18mm();
motorConfig.setMotor( mtr);
motorConfig.setEjectionDelay(0.0);
inner.setMotorConfig( motorConfig, fcid[0]);
inner.setMotorConfig( motorConfig, TEST_FCID_0);
}
{
MotorConfiguration motorConfig = new MotorConfiguration(inner,fcid[1]);
MotorConfiguration motorConfig = new MotorConfiguration(inner,TEST_FCID_1);
Motor mtr = TestRockets.generateMotor_B4_18mm();
motorConfig.setMotor( mtr);
motorConfig.setEjectionDelay(3.0);
inner.setMotorConfig( motorConfig, fcid[1]);
inner.setMotorConfig( motorConfig, TEST_FCID_1);
}
{
MotorConfiguration motorConfig = new MotorConfiguration(inner,fcid[2]);
MotorConfiguration motorConfig = new MotorConfiguration(inner, TEST_FCID_2);
Motor mtr = TestRockets.generateMotor_C6_18mm();
motorConfig.setEjectionDelay(3.0);
motorConfig.setMotor( mtr);
inner.setMotorConfig( motorConfig, fcid[2]);
inner.setMotorConfig( motorConfig, TEST_FCID_2);
}
{
MotorConfiguration motorConfig = new MotorConfiguration(inner,fcid[3]);
MotorConfiguration motorConfig = new MotorConfiguration(inner,TEST_FCID_3);
Motor mtr = TestRockets.generateMotor_C6_18mm();
motorConfig.setEjectionDelay(5.0);
motorConfig.setMotor( mtr);
inner.setMotorConfig( motorConfig, fcid[3]);
inner.setMotorConfig( motorConfig, TEST_FCID_3);
}
{
MotorConfiguration motorConfig = new MotorConfiguration(inner,fcid[4]);
MotorConfiguration motorConfig = new MotorConfiguration(inner,TEST_FCID_4);
Motor mtr = TestRockets.generateMotor_C6_18mm();
motorConfig.setEjectionDelay(7.0);
motorConfig.setMotor( mtr);
inner.setMotorConfig( motorConfig, fcid[4]);
inner.setMotorConfig( motorConfig, TEST_FCID_4);
}
}
@ -526,13 +524,33 @@ public class TestRockets {
bodytube.setMaterial(material);
finset.setMaterial(material);
// preserve default default configuration of rocket -- to test what the default is set to upon initialization.
rocket.enableEvents();
return rocket;
}
public static final void splitRocketFins( BodyTube body, TrapezoidFinSet fins, int finCount){
// actually remove the fins
body.removeChild(fins);
TrapezoidFinSet template = fins;
template.setFinCount(1);
// and manually add in the equivalent the others
for(int finNumber=1; finNumber<finCount; ++finNumber){
final double rootChord = template.getRootChord();
final double tipChord = template.getTipChord();
final double sweep = template.getSweep();
final double height = template.getHeight();
final TrapezoidFinSet singleFin = new TrapezoidFinSet(1, rootChord, tipChord, sweep, height);
singleFin.setAngleOffset( finNumber * Math.PI * 2.0 / finCount);
singleFin.setThickness( template.getThickness());
singleFin.setAxialMethod( template.getAxialMethod());
singleFin.setName(String.format("Single Fin #%d", finNumber));
body.addChild(singleFin);
}
}
// This is an extra stage tacked onto the end of an Estes Alpha III
// http://www.rocketreviews.com/alpha-iii---estes-221256.html
//
@ -586,16 +604,16 @@ public class TestRockets {
boosterMMT.setLength(0.05);
boosterMMT.setMotorMount(true);
{
MotorConfiguration motorConfig= new MotorConfiguration(boosterMMT, ESTES_ALPHA_III_FCID[1] );
MotorConfiguration motorConfig= new MotorConfiguration(boosterMMT, TEST_FCID_1 );
Motor mtr = generateMotor_D21_18mm();
motorConfig.setMotor(mtr);
boosterMMT.setMotorConfig( motorConfig, ESTES_ALPHA_III_FCID[1]);
boosterMMT.setMotorConfig( motorConfig, TEST_FCID_1);
}
boosterBody.addChild(boosterMMT);
}
}
rocket.setSelectedConfiguration( ESTES_ALPHA_III_FCID[1] );
rocket.setSelectedConfiguration( TEST_FCID_1 );
rocket.getSelectedConfiguration().setAllStages();
rocket.enableEvents();
@ -748,7 +766,7 @@ public class TestRockets {
auxfinset.setCrossSection(CrossSection.AIRFOIL);
auxfinset.setAxialMethod(AxialMethod.TOP);
auxfinset.setAxialOffset(0.28);
auxfinset.setBaseRotation(Math.PI / 2);
auxfinset.setAngleOffset(Math.PI / 2);
tube1.addChild(auxfinset);
coupler = new TubeCoupler();
@ -826,7 +844,7 @@ public class TestRockets {
finset.setSweep(0.3);
finset.setAxialMethod(AxialMethod.BOTTOM);
finset.setAxialOffset(-0.03);
finset.setBaseRotation(Math.PI / 2);
finset.setAngleOffset(Math.PI / 2);
tube3.addChild(finset);
finset.setCantAngle(0 * Math.PI / 180);
@ -1012,7 +1030,7 @@ public class TestRockets {
boosterBody.addChild(boosterFins);
boosterFins.setName("Booster Fins");
boosterFins.setFinCount(3);
boosterFins.setBaseRotation( Math.PI / 4);
boosterFins.setAngleOffset( Math.PI / 4);
boosterFins.setThickness(0.003);
boosterFins.setCrossSection(CrossSection.ROUNDED);
boosterFins.setRootChord(0.32);
@ -1021,12 +1039,6 @@ public class TestRockets {
boosterFins.setSweep(0.18);
boosterFins.setAxialMethod(AxialMethod.BOTTOM);
boosterFins.setAxialOffset(0.0);
// cp:(1.17873,0.10422,0.02722,w=6.07405) (1 fin case)
// cp:(1.17873,-0.10422,-0.02722,w=6.07405) (1 fin case)
// cp:(1.17873,0.10422,0.02722,w=12.14810) (2 fin case)
// cp:(1.17873,-0.10422,-0.02722,w=12.14810) (2 fin case)
// cp:(1.17873,0.00000,0.00000,w=9.11107) (3 fin case)
// cp:(1.17873,0.00000,0.00000,w=9.11107) (3 fin case)
}
}
@ -1148,7 +1160,7 @@ public class TestRockets {
TrapezoidFinSet endPlate = new TrapezoidFinSet(endPlateCount, endPlateRootChord, endPlateTipChord, endPlateSweep, endPlateHeight);
phantom.addChild(endPlate);
endPlate.setName("End plates");
endPlate.setBaseRotation(endPlateRotation);
endPlate.setAngleOffset(endPlateRotation);
endPlate.setAxialMethod(endPlateAxialMethod);
endPlate.setAxialOffset(endPlateAxialOffset);
endPlate.setThickness(endPlateThickness);

91
core/test/net/sf/openrocket/aerodynamics/BarrowmanCalculatorTest.java
View File

@ -15,6 +15,7 @@ import net.sf.openrocket.ServicesForTesting;
import net.sf.openrocket.plugin.PluginModule;
import net.sf.openrocket.rocketcomponent.AxialStage;
import net.sf.openrocket.rocketcomponent.BodyTube;
import net.sf.openrocket.rocketcomponent.FinSet;
import net.sf.openrocket.rocketcomponent.FlightConfiguration;
import net.sf.openrocket.rocketcomponent.NoseCone;
import net.sf.openrocket.rocketcomponent.ParallelStage;
@ -129,22 +130,100 @@ public class BarrowmanCalculatorTest {
}{
boosterFins.setFinCount(2);
final Coordinate cp_2fin = calc.getCP(config, conditions, warnings);
assertEquals(" Falcon 9 Heavy CNa value is incorrect:", 27.585207667168696, cp_2fin.weight, EPSILON);
assertEquals(" Falcon 9 Heavy CP x value is incorrect:", 1.0757127676940474, cp_2fin.x, EPSILON);
assertEquals(" Falcon 9 Heavy CNa value is incorrect:", 15.43711196967902, cp_2fin.weight, EPSILON);
assertEquals(" Falcon 9 Heavy CP x value is incorrect:", 0.9946423753010524, cp_2fin.x, EPSILON);
assertEquals(" Falcon 9 Heavy CP y value is incorrect:", 0.0, cp_2fin.y, EPSILON);
assertEquals(" Falcon 9 Heavy CP z value is incorrect:", 0.0, cp_2fin.z, EPSILON);
}{
boosterFins.setFinCount(1);
final Coordinate cp_1fin = calc.getCP(config, conditions, warnings);
assertEquals(" Falcon 9 Heavy CNa value is incorrect:", 15.43711196967902, cp_1fin.weight, EPSILON);
assertEquals(" Falcon 9 Heavy CP x value is incorrect:", 0.99464, cp_1fin.x, EPSILON);
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:", 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]
}
}
@Test
public void testFinCountEffect() {
final BarrowmanCalculator calc = new BarrowmanCalculator();
final WarningSet warnings = new WarningSet();
final Rocket rocket = TestRockets.makeEstesAlphaIII();
final FlightConfiguration config = rocket.getSelectedConfiguration();
final FlightConditions conditions = new FlightConditions(config);
{
((FinSet)rocket.getChild(0).getChild(1).getChild(0)).setFinCount(4);
final Coordinate wholeRocketCP = calc.getCP(config, conditions, warnings);
assertEquals("Split-Fin Rocket CNa value is incorrect:", 34.19591165, wholeRocketCP.weight, EPSILON);
assertEquals("Split-Fin Rocket CP x value is incorrect:", 0.22724216, wholeRocketCP.x, EPSILON);
}{
((FinSet)rocket.getChild(0).getChild(1).getChild(0)).setFinCount(3);
final Coordinate wholeRocketCP = calc.getCP(config, conditions, warnings);
assertEquals("Split-Fin Rocket CNa value is incorrect:", 26.14693374, wholeRocketCP.weight, EPSILON);
assertEquals("Split-Fin Rocket CP x value is incorrect:", 0.22351541, wholeRocketCP.x, EPSILON);
}{
((FinSet)rocket.getChild(0).getChild(1).getChild(0)).setFinCount(2);
final Coordinate wholeRocketCP = calc.getCP(config, conditions, warnings);
assertEquals("Split-Fin Rocket CNa value is incorrect:", 2.0, wholeRocketCP.weight, EPSILON);
assertEquals("Split-Fin Rocket CP x value is incorrect:", 0.032356, wholeRocketCP.x, EPSILON);
}{
((FinSet)rocket.getChild(0).getChild(1).getChild(0)).setFinCount(1);
final Coordinate wholeRocketCP = calc.getCP(config, conditions, warnings);
assertEquals("Split-Fin Rocket CNa value is incorrect:", 2.0, wholeRocketCP.weight, EPSILON);
assertEquals("Split-Fin Rocket CP x value is incorrect:", 0.032356, wholeRocketCP.x, EPSILON);
}
}
@Test
public void testCpSplitTripleFin() {
final BarrowmanCalculator calc = new BarrowmanCalculator();
final WarningSet warnings = new WarningSet();
final Rocket rocket = TestRockets.makeEstesAlphaIII();
final FlightConfiguration config = rocket.getSelectedConfiguration();
final FlightConditions conditions = new FlightConditions(config);
{
final Coordinate wholeRocketCP = calc.getCP(config, conditions, warnings);
assertEquals("Split-Fin Rocket CNa value is incorrect:", 26.14693374, wholeRocketCP.weight, EPSILON);
assertEquals("Split-Fin Rocket CP x value is incorrect:", 0.22351541, wholeRocketCP.x, EPSILON);
}{
final BodyTube body = (BodyTube)rocket.getChild(0).getChild(1);
final TrapezoidFinSet fins = (TrapezoidFinSet)body.getChild(0);
fins.setAngleOffset(0);
TestRockets.splitRocketFins(body, fins, 3);
final Coordinate wholeRocketCP = calc.getCP(config, conditions, warnings);
assertEquals("Split-Fin Rocket CNa value is incorrect:", 26.14693374, wholeRocketCP.weight, EPSILON);
assertEquals("Split-Fin Rocket CP x value is incorrect:", 0.22351541, wholeRocketCP.x, EPSILON);
}
}
@Test
public void testCpSplitQuadrupleFin() {
final BarrowmanCalculator calc = new BarrowmanCalculator();
final WarningSet warnings = new WarningSet();
final Rocket rocket = TestRockets.makeEstesAlphaIII();
final FlightConfiguration config = rocket.getSelectedConfiguration();
final FlightConditions conditions = new FlightConditions(config);
{
((FinSet)rocket.getChild(0).getChild(1).getChild(0)).setFinCount(4);
final Coordinate wholeRocketCP = calc.getCP(config, conditions, warnings);
assertEquals("Split-Fin Rocket CNa value is incorrect:", 34.19591165, wholeRocketCP.weight, EPSILON);
assertEquals("Split-Fin Rocket CP x value is incorrect:", 0.22724, wholeRocketCP.x, EPSILON);
}{
final BodyTube body = (BodyTube)rocket.getChild(0).getChild(1);
final TrapezoidFinSet fins = (TrapezoidFinSet)body.getChild(0);
TestRockets.splitRocketFins(body, fins, 4);
final Coordinate wholeRocketCP = calc.getCP(config, conditions, warnings);
assertEquals("Split-Fin Rocket CNa value is incorrect:", 34.19591165, wholeRocketCP.weight, EPSILON);
assertEquals("Split-Fin Rocket CP x value is incorrect:", 0.22724, wholeRocketCP.x, EPSILON);
}
}
// test rocket with endplates on fins. Comments tracing
// calculation of CP are in TestRockets.makeEndPlateRocket().
@Test