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Create RocketComponentCalc::calculateFrictionCD()

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Move actual friction CD calculation code into subclasses of RocketComponentCalc()

LaunchLugCalc adds so little wetted area it isn't worth bothering with, so isn't calculated (wasn't calculated before, either)

TubeFinSetCalc also doesn't calculate it; that's coming next.
This commit is contained in:
JoePfeiffer 2022-04-05 19:30:10 -06:00
parent 56949560c4
commit 632b48f8df
6 changed files with 53 additions and 31 deletions
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45
core/src/net/sf/openrocket/aerodynamics/BarrowmanCalculator.java
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@ -323,7 +323,7 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
* @return friction drag for entire rocket
*/
private double calculateFrictionCD(FlightConfiguration configuration, FlightConditions conditions,
Map<RocketComponent, AerodynamicForces> map, WarningSet set) {
Map<RocketComponent, AerodynamicForces> map, WarningSet warningSet) {
double mach = conditions.getMach();
double Re = calculateReynoldsNumber(configuration, conditions);
@ -341,8 +341,8 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
* for thickness as we go on.
*/
double finFriction = 0;
double bodyFriction = 0;
double finFrictionCD = 0;
double bodyFrictionCD = 0;
double maxR = 0, minX = Double.MAX_VALUE, maxX = 0;
double[] roughnessLimited = new double[Finish.values().length];
@ -351,8 +351,11 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
final InstanceMap imap = configuration.getActiveInstances();
for(Map.Entry<RocketComponent, ArrayList<InstanceContext>> entry: imap.entrySet() ) {
final RocketComponent c = entry.getKey();
//Handle Overriden CD for Whole Rocket
if (!c.isAerodynamic())
continue;
// Handle Overriden CD for Whole Rocket
if(c.isCDOverridden()) {
continue;
}
@ -389,20 +392,11 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
// iterate across component instances
final ArrayList<InstanceContext> contextList = entry.getValue();
for(InstanceContext context: contextList ) {
// Calculate the friction drag:
double componentFrictionCD = calcMap.get(c).calculateFrictionCD(conditions, componentCf, warningSet);
if (c instanceof SymmetricComponent) {
SymmetricComponent s = (SymmetricComponent) c;
bodyFriction += componentCf * s.getComponentWetArea();
if (map != null) {
// Corrected later
map.get(c).setFrictionCD(componentCf * s.getComponentWetArea()
/ conditions.getRefArea());
}
bodyFrictionCD += componentFrictionCD;
final double componentMinX = context.getLocation().x;
minX = Math.min(minX, componentMinX);
@ -414,16 +408,11 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
maxR = Math.max(maxR, componentMaxR);
} else if (c instanceof FinSet) {
FinSet f = (FinSet) c;
double mac = ((FinSetCalc) calcMap.get(c)).getMACLength();
double cd = componentCf * (1 + 2 * f.getThickness() / mac) *
2 * f.getPlanformArea();
finFriction += cd;
if (map != null) {
map.get(c).setFrictionCD(cd / conditions.getRefArea());
}
finFrictionCD += componentFrictionCD;
}
if (map != null) {
map.get(c).setFrictionCD(componentFrictionCD);
}
}
}
@ -441,7 +430,7 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
}
}
return (finFriction + correction * bodyFriction) / conditions.getRefArea();
return finFrictionCD + correction * bodyFrictionCD;
}

6
core/src/net/sf/openrocket/aerodynamics/barrowman/FinSetCalc.java
View File

@ -621,6 +621,12 @@ public class FinSetCalc extends RocketComponentCalc {
// }
//
// }
@Override
public double calculateFrictionCD(FlightConditions conditions, double componentCf, WarningSet warnings) {
double cd = componentCf * (1 + 2 * thickness / macLength) * 2;
return cd;
}
@Override
public double calculatePressureCD(FlightConditions conditions,

6
core/src/net/sf/openrocket/aerodynamics/barrowman/LaunchLugCalc.java
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@ -30,6 +30,12 @@ public class LaunchLugCalc extends RocketComponentCalc {
// Nothing to be done
}
@Override
public double calculateFrictionCD(FlightConditions conditions, double componentCf, WarningSet warnings) {
// launch lug doesn't add enough area to worry about
return 0;
}
@Override
public double calculatePressureCD(FlightConditions conditions,
double stagnationCD, double baseCD, WarningSet warnings) {

12
core/src/net/sf/openrocket/aerodynamics/barrowman/RocketComponentCalc.java
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@ -28,6 +28,16 @@ public abstract class RocketComponentCalc {
public abstract void calculateNonaxialForces(FlightConditions conditions, Transformation transform,
AerodynamicForces forces, WarningSet warnings);
/**
* Calculates the friction drag of the component.
*
* @param conditions the flight conditions
* @param componentCF component coefficient of friction, calculated in BarrowmanCalculator
* @param warnings set in which to to store possible warnings
* @return the friction drag coefficient of the component
*/
public abstract double calculateFrictionCD(FlightConditions conditions, double componentCf, WarningSet warnings);
/**
* Calculates the pressure drag of the component. This component does NOT include
@ -37,7 +47,7 @@ public abstract class RocketComponentCalc {
* @param stagnationCD the current stagnation drag coefficient
* @param baseCD the current base drag coefficient
* @param warnings set in which to store possible warnings
* @return the pressure drag of the component
* @return the pressure drag coefficient of the component
*/
public abstract double calculatePressureCD(FlightConditions conditions,
double stagnationCD, double baseCD, WarningSet warnings);

9
core/src/net/sf/openrocket/aerodynamics/barrowman/SymmetricComponentCalc.java
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@ -45,6 +45,7 @@ public class SymmetricComponentCalc extends RocketComponentCalc {
private final double frontalArea;
private final double fullVolume;
private final double planformArea, planformCenter;
private final double wetArea;
private final double sinphi;
public SymmetricComponentCalc(RocketComponent c) {
@ -53,7 +54,6 @@ public class SymmetricComponentCalc extends RocketComponentCalc {
throw new IllegalArgumentException("Illegal component type " + c);
}
SymmetricComponent component = (SymmetricComponent) c;
length = component.getLength();
foreRadius = component.getForeRadius();
@ -63,6 +63,8 @@ public class SymmetricComponentCalc extends RocketComponentCalc {
fullVolume = component.getFullVolume();
planformArea = component.getComponentPlanformArea();
planformCenter = component.getComponentPlanformCenter();
wetArea = component.getComponentWetArea();
if (component instanceof BodyTube) {
shape = null;
@ -174,7 +176,10 @@ public class SymmetricComponentCalc extends RocketComponentCalc {
conditions.getSinAOA() * conditions.getSincAOA()); // sin(aoa)^2 / aoa
}
@Override
public double calculateFrictionCD(FlightConditions conditions, double componentCf, WarningSet warningSet) {
return componentCf * wetArea / conditions.getRefArea();
}
private LinearInterpolator interpolator = null;

6
core/src/net/sf/openrocket/aerodynamics/barrowman/TubeFinSetCalc.java
View File

@ -672,5 +672,11 @@ public class TubeFinSetCalc extends RocketComponentCalc {
return 3 * component.getFinCount();
}
@Override
public double calculateFrictionCD(FlightConditions conditions, double componentCf, WarningSet warnings) {
// launch lug doesn't add enough area to worry about
return 0;
}
}