Merge pull request #2570 from SiboVG/improve-beta
Clamp beta factor (compressibility correction) in transonic region + apply it in supersonic region
This commit is contained in:
Joe Pfeiffer
GitHub
commit
6076d9ae09
@ -22,6 +22,7 @@ import info.openrocket.core.util.ModID;
|
||||
* @author Sampo Niskanen <sampo.niskanen@iki.fi>
|
||||
*/
|
||||
public class FlightConditions implements Cloneable, ChangeSource, Monitorable {
|
||||
private static final double MIN_BETA = 0.25;
|
||||
|
||||
private List<EventListener> listenerList = new ArrayList<>();
|
||||
private EventObject event = new EventObject(this);
|
||||
@ -55,7 +56,7 @@ public class FlightConditions implements Cloneable, ChangeSource, Monitorable {
|
||||
* Sqrt(1 - M^2) for M<1
|
||||
* Sqrt(M^2 - 1) for M>1
|
||||
*/
|
||||
private double beta = MathUtil.safeSqrt(1 - mach * mach);
|
||||
private double beta = calculateBeta(mach);
|
||||
|
||||
/** Current roll rate. */
|
||||
private double rollRate = 0;
|
||||
@ -243,10 +244,7 @@ public class FlightConditions implements Cloneable, ChangeSource, Monitorable {
|
||||
return;
|
||||
|
||||
this.mach = mach;
|
||||
if (mach < 1)
|
||||
this.beta = MathUtil.safeSqrt(1 - mach * mach);
|
||||
else
|
||||
this.beta = MathUtil.safeSqrt(mach * mach - 1);
|
||||
this.beta = calculateBeta(mach);
|
||||
|
||||
fireChangeEvent();
|
||||
}
|
||||
@ -288,6 +286,19 @@ public class FlightConditions implements Cloneable, ChangeSource, Monitorable {
|
||||
return beta;
|
||||
}
|
||||
|
||||
/**
|
||||
* Calculate the beta value (compressibility factor/Prandtl-Glauert correction factor) for the given Mach number.
|
||||
* @param mach the Mach number.
|
||||
* @return the beta value.
|
||||
*/
|
||||
private static double calculateBeta(double mach) {
|
||||
if (mach < 1) {
|
||||
return MathUtil.max(MIN_BETA, MathUtil.safeSqrt(1 - mach * mach));
|
||||
} else {
|
||||
return MathUtil.max(MIN_BETA, MathUtil.safeSqrt(mach * mach - 1));
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* @return the current roll rate.
|
||||
*/
|
||||
|
||||
@ -162,9 +162,6 @@ public class FinSetCalc extends RocketComponentCalc {
|
||||
// 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);
|
||||
// logger.debug("Component macLength = {}", macLength);
|
||||
// logger.debug("Component x = {}", x);
|
||||
|
||||
|
||||
// Calculate roll forces, reduce forcing above stall angle
|
||||
@ -176,17 +173,12 @@ public class FinSetCalc extends RocketComponentCalc {
|
||||
forces.setCrollForce((macSpan + r) * cna1 * (1 + tau) * cantAngle / conditions.getRefLength());
|
||||
|
||||
if (conditions.getAOA() > STALL_ANGLE) {
|
||||
// System.out.println("Fin stalling in roll");
|
||||
forces.setCrollForce(forces.getCrollForce() * MathUtil.clamp(
|
||||
1 - (conditions.getAOA() - STALL_ANGLE) / (STALL_ANGLE / 2), 0, 1));
|
||||
}
|
||||
forces.setCrollDamp(calculateDampingMoment(conditions));
|
||||
forces.setCroll(forces.getCrollForce() - forces.getCrollDamp());
|
||||
|
||||
// System.out.printf(component.getName() + ": roll rate:%.3f force:%.3f damp:%.3f " +
|
||||
// "total:%.3f\n",
|
||||
// conditions.getRollRate(), forces.CrollForce, forces.CrollDamp, forces.Croll);
|
||||
|
||||
forces.setCNa(cna);
|
||||
forces.setCN(cna * MathUtil.min(conditions.getAOA(), STALL_ANGLE));
|
||||
forces.setCP(new Coordinate(x, 0, 0, cna));
|
||||
@ -349,7 +341,6 @@ public class FinSetCalc extends RocketComponentCalc {
|
||||
double y = i * dy;
|
||||
|
||||
macLength += length * length;
|
||||
//logger.debug("macLength = {}, length = {}, i = {}", macLength, length, i);
|
||||
macSpan += y * length;
|
||||
macLead += chordLead[i] * length;
|
||||
area += length;
|
||||
@ -408,10 +399,6 @@ public class FinSetCalc extends RocketComponentCalc {
|
||||
K1 = new LinearInterpolator(x, k1);
|
||||
K2 = new LinearInterpolator(x, k2);
|
||||
K3 = new LinearInterpolator(x, k3);
|
||||
|
||||
// System.out.println("K1[m="+CNA_SUPERSONIC+"] = "+k1[0]);
|
||||
// System.out.println("K2[m="+CNA_SUPERSONIC+"] = "+k2[0]);
|
||||
// System.out.println("K3[m="+CNA_SUPERSONIC+"] = "+k3[0]);
|
||||
}
|
||||
|
||||
protected double calculateFinCNa1(FlightConditions conditions) {
|
||||
@ -445,8 +432,6 @@ public class FinSetCalc extends RocketComponentCalc {
|
||||
K3.getValue(CNA_SUPERSONIC) * pow2(alpha)) / ref;
|
||||
superD = -finArea / ref * 2 * CNA_SUPERSONIC / CNA_SUPERSONIC_B;
|
||||
|
||||
// System.out.println("subV="+subV+" superV="+superV+" subD="+subD+" superD="+superD);
|
||||
|
||||
return cnaInterpolator.interpolate(mach, subV, superV, subD, superD, 0);
|
||||
}
|
||||
|
||||
@ -473,24 +458,16 @@ public class FinSetCalc extends RocketComponentCalc {
|
||||
}
|
||||
sum = sum * (span / DIVISIONS) * 2 * Math.PI / conditions.getBeta() /
|
||||
(conditions.getRefArea() * conditions.getRefLength());
|
||||
|
||||
// System.out.println("SPECIAL: " +
|
||||
// (MathUtil.sign(rollRate) * sum));
|
||||
|
||||
return MathUtil.sign(rollRate) * sum;
|
||||
}
|
||||
|
||||
if (mach <= CNA_SUBSONIC) {
|
||||
// System.out.println("BASIC: "+
|
||||
// (2*Math.PI * rollRate * rollSum /
|
||||
// (conditions.getRefArea() * conditions.getRefLength() *
|
||||
// conditions.getVelocity() * conditions.getBeta())));
|
||||
|
||||
return 2 * Math.PI * rollRate * rollSum /
|
||||
(conditions.getRefArea() * conditions.getRefLength() *
|
||||
conditions.getVelocity() * conditions.getBeta());
|
||||
}
|
||||
if (mach >= CNA_SUPERSONIC) {
|
||||
|
||||
double vel = conditions.getVelocity();
|
||||
double k1 = K1.getValue(mach);
|
||||
double k2 = K2.getValue(mach);
|
||||
@ -511,7 +488,6 @@ public class FinSetCalc extends RocketComponentCalc {
|
||||
}
|
||||
|
||||
// Transonic, do linear interpolation
|
||||
|
||||
FlightConditions cond = conditions.clone();
|
||||
cond.setMach(CNA_SUBSONIC - 0.01);
|
||||
double subsonic = calculateDampingMoment(cond);
|
||||
@ -532,7 +508,7 @@ public class FinSetCalc extends RocketComponentCalc {
|
||||
*/
|
||||
private double calculateCPPos(FlightConditions cond) {
|
||||
double m = cond.getMach();
|
||||
// logger.debug("m = {} ", m);
|
||||
|
||||
if (m <= 0.5) {
|
||||
// At subsonic speeds CP at quarter chord
|
||||
return 0.25;
|
||||
@ -551,7 +527,7 @@ public class FinSetCalc extends RocketComponentCalc {
|
||||
val += v * x;
|
||||
x *= m;
|
||||
}
|
||||
// logger.debug("val = {}", val);
|
||||
|
||||
return val;
|
||||
}
|
||||
|
||||
|
||||
@ -0,0 +1,213 @@
|
||||
package info.openrocket.core.aerodynamics;
|
||||
|
||||
import static org.junit.jupiter.api.Assertions.*;
|
||||
|
||||
import com.google.inject.Guice;
|
||||
import com.google.inject.Injector;
|
||||
import com.google.inject.Module;
|
||||
import info.openrocket.core.ServicesForTesting;
|
||||
import info.openrocket.core.document.OpenRocketDocument;
|
||||
import info.openrocket.core.document.OpenRocketDocumentFactory;
|
||||
import info.openrocket.core.plugin.PluginModule;
|
||||
import info.openrocket.core.rocketcomponent.BodyTube;
|
||||
import info.openrocket.core.rocketcomponent.Rocket;
|
||||
import info.openrocket.core.startup.Application;
|
||||
import org.junit.jupiter.api.BeforeEach;
|
||||
import org.junit.jupiter.api.Test;
|
||||
|
||||
import info.openrocket.core.models.atmosphere.AtmosphericConditions;
|
||||
import info.openrocket.core.rocketcomponent.FlightConfiguration;
|
||||
import info.openrocket.core.util.Coordinate;
|
||||
|
||||
class FlightConditionsTest {
|
||||
private FlightConditions conditions;
|
||||
private static final double EPSILON = 1e-6;
|
||||
|
||||
private Rocket rocket;
|
||||
|
||||
@BeforeEach
|
||||
void setUp() {
|
||||
com.google.inject.Module applicationModule = new ServicesForTesting();
|
||||
Module pluginModule = new PluginModule();
|
||||
|
||||
Injector injector = Guice.createInjector(applicationModule, pluginModule);
|
||||
Application.setInjector(injector);
|
||||
|
||||
OpenRocketDocument document = OpenRocketDocumentFactory.createNewRocket();
|
||||
this.rocket = document.getRocket();
|
||||
BodyTube bodyTube = new BodyTube();
|
||||
bodyTube.setLength(1.0);
|
||||
bodyTube.setOuterRadius(0.05);
|
||||
this.rocket.getChild(0).addChild(bodyTube);
|
||||
|
||||
FlightConfiguration mockConfig = new FlightConfiguration(rocket);
|
||||
this.conditions = new FlightConditions(mockConfig);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetRefLength() {
|
||||
double expectedLength = ((BodyTube) rocket.getChild(0).getChild(0)).getOuterRadius() * 2;
|
||||
assertEquals(expectedLength, conditions.getRefLength(), EPSILON);
|
||||
|
||||
conditions.setRefLength(2.0);
|
||||
assertEquals(2.0, conditions.getRefLength(), EPSILON);
|
||||
assertEquals(Math.PI, conditions.getRefArea(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetRefArea() {
|
||||
// Get the actual reference area from FlightConditions
|
||||
double actualRefArea = conditions.getRefArea();
|
||||
|
||||
// Test that setting this area results in the same value
|
||||
conditions.setRefArea(actualRefArea);
|
||||
assertEquals(actualRefArea, conditions.getRefArea(), EPSILON);
|
||||
|
||||
// Test that setting a new area works correctly
|
||||
double newArea = 4.0;
|
||||
conditions.setRefArea(newArea);
|
||||
assertEquals(newArea, conditions.getRefArea(), EPSILON);
|
||||
assertEquals(Math.sqrt(newArea / Math.PI) * 2, conditions.getRefLength(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetAOA() {
|
||||
conditions.setAOA(Math.PI / 4);
|
||||
assertEquals(Math.PI / 4, conditions.getAOA(), EPSILON);
|
||||
assertEquals(Math.sin(Math.PI / 4), conditions.getSinAOA(), EPSILON);
|
||||
assertEquals(Math.sin(Math.PI / 4) / (Math.PI / 4), conditions.getSincAOA(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetTheta() {
|
||||
conditions.setTheta(Math.PI / 3);
|
||||
assertEquals(Math.PI / 3, conditions.getTheta(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetMach() {
|
||||
conditions.setMach(0.2);
|
||||
assertEquals(0.2, conditions.getMach(), EPSILON);
|
||||
assertEquals(0.9797958971, conditions.getBeta(), EPSILON);
|
||||
|
||||
conditions.setMach(0.8);
|
||||
assertEquals(0.8, conditions.getMach(), EPSILON);
|
||||
assertEquals(0.6, conditions.getBeta(), EPSILON);
|
||||
|
||||
conditions.setMach(0.9999999999);
|
||||
assertEquals(0.9999999999, conditions.getMach(), EPSILON);
|
||||
assertEquals(0.25, conditions.getBeta(), EPSILON);
|
||||
|
||||
conditions.setMach(1.00000000001);
|
||||
assertEquals(1.00000000001, conditions.getMach(), EPSILON);
|
||||
assertEquals(0.25, conditions.getBeta(), EPSILON);
|
||||
|
||||
conditions.setMach(1.3);
|
||||
assertEquals(1.3, conditions.getMach(), EPSILON);
|
||||
assertEquals(0.8306623863, conditions.getBeta(), EPSILON);
|
||||
|
||||
conditions.setMach(3);
|
||||
assertEquals(3, conditions.getMach(), EPSILON);
|
||||
assertEquals(2.8284271247, conditions.getBeta(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetVelocity() {
|
||||
AtmosphericConditions atm = new AtmosphericConditions();
|
||||
conditions.setAtmosphericConditions(atm);
|
||||
|
||||
double expectedMachSpeed = atm.getMachSpeed();
|
||||
conditions.setVelocity(expectedMachSpeed / 2);
|
||||
|
||||
assertEquals(0.5, conditions.getMach(), EPSILON);
|
||||
assertEquals(expectedMachSpeed / 2, conditions.getVelocity(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetRollRate() {
|
||||
conditions.setRollRate(5.0);
|
||||
assertEquals(5.0, conditions.getRollRate(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetPitchRate() {
|
||||
conditions.setPitchRate(2.5);
|
||||
assertEquals(2.5, conditions.getPitchRate(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetYawRate() {
|
||||
conditions.setYawRate(1.5);
|
||||
assertEquals(1.5, conditions.getYawRate(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetPitchCenter() {
|
||||
Coordinate center = new Coordinate(1.0, 2.0, 3.0);
|
||||
conditions.setPitchCenter(center);
|
||||
assertEquals(center, conditions.getPitchCenter());
|
||||
}
|
||||
|
||||
@Test
|
||||
void testClone() {
|
||||
conditions.setAOA(Math.PI / 6);
|
||||
conditions.setMach(0.7);
|
||||
conditions.setRollRate(3.0);
|
||||
AtmosphericConditions atm = new AtmosphericConditions(280, 90000);
|
||||
conditions.setAtmosphericConditions(atm);
|
||||
|
||||
FlightConditions cloned = conditions.clone();
|
||||
|
||||
assertNotSame(conditions, cloned);
|
||||
assertEquals(conditions.getAOA(), cloned.getAOA(), EPSILON);
|
||||
assertEquals(conditions.getMach(), cloned.getMach(), EPSILON);
|
||||
assertEquals(conditions.getRollRate(), cloned.getRollRate(), EPSILON);
|
||||
assertEquals(conditions.getAtmosphericConditions().getTemperature(),
|
||||
cloned.getAtmosphericConditions().getTemperature(), EPSILON);
|
||||
assertEquals(conditions.getAtmosphericConditions().getPressure(),
|
||||
cloned.getAtmosphericConditions().getPressure(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testEquals() {
|
||||
FlightConditions conditions1 = new FlightConditions(null);
|
||||
FlightConditions conditions2 = new FlightConditions(null);
|
||||
|
||||
conditions1.setAOA(Math.PI / 6);
|
||||
conditions1.setMach(0.7);
|
||||
conditions2.setAOA(Math.PI / 6);
|
||||
conditions2.setMach(0.7);
|
||||
|
||||
assertTrue(conditions1.equals(conditions2));
|
||||
|
||||
conditions2.setMach(0.8);
|
||||
assertFalse(conditions1.equals(conditions2));
|
||||
}
|
||||
|
||||
@Test
|
||||
void testSetAndGetAtmosphericConditions() {
|
||||
AtmosphericConditions atm = new AtmosphericConditions(280, 90000);
|
||||
conditions.setAtmosphericConditions(atm);
|
||||
|
||||
assertEquals(280, conditions.getAtmosphericConditions().getTemperature(), EPSILON);
|
||||
assertEquals(90000, conditions.getAtmosphericConditions().getPressure(), EPSILON);
|
||||
}
|
||||
|
||||
@Test
|
||||
void testGetVelocityWithChangedAtmosphere() {
|
||||
AtmosphericConditions atm = new AtmosphericConditions(280, 90000);
|
||||
conditions.setAtmosphericConditions(atm);
|
||||
conditions.setMach(0.5);
|
||||
|
||||
double expectedVelocity = 0.5 * atm.getMachSpeed();
|
||||
assertEquals(expectedVelocity, conditions.getVelocity(), EPSILON);
|
||||
|
||||
// Change atmospheric conditions
|
||||
atm.setTemperature(300);
|
||||
conditions.setAtmosphericConditions(atm);
|
||||
|
||||
// Velocity should change with new atmospheric conditions
|
||||
expectedVelocity = 0.5 * atm.getMachSpeed();
|
||||
assertEquals(expectedVelocity, conditions.getVelocity(), EPSILON);
|
||||
}
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user