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Warn that fins with zero area will not affect aerodynamics

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Keep fins with zero area from getting NaN errors
This commit is contained in:
JoePfeiffer 2023-02-26 15:42:15 -07:00
parent 9a7b042039
commit 0ea93a7821
3 changed files with 29 additions and 10 deletions
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1
core/resources/l10n/messages.properties
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@ -1882,6 +1882,7 @@ Warning.PODSET_FORWARD = In-line podset forward of parent airframe component
Warning.PODSET_OVERLAP = In-line podset overlaps parent airframe component
Warning.THICK_FIN = Thick fins may not simulate accurately.
Warning.JAGGED_EDGED_FIN = Jagged-edged fin predictions may be inaccurate.
Warning.ZERO_AREA_FIN = Fins with zero area will not affect aerodynamics
Warning.LISTENERS_AFFECTED = Listeners modified the flight simulation
Warning.RECOVERY_DEPLOYMENT_WHILE_BURNING = Recovery device opened while motor still burning.
Warning.FILE_INVALID_PARAMETER = Invalid parameter encountered, ignoring.

4
core/src/net/sf/openrocket/aerodynamics/Warning.java
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@ -382,6 +382,10 @@ public abstract class Warning {
////Jagged-edged fin predictions may be inaccurate.
public static final Warning JAGGED_EDGED_FIN = new Other(trans.get("Warning.JAGGED_EDGED_FIN"));
/** A <code>Warning</code> that the fins have a zero area. */
////Fins with no area will not affect aerodynamics
public static final Warning ZERO_AREA_FIN = new Other(trans.get("Warning.ZERO_AREA_FIN"));
/** A <code>Warning</code> that simulation listeners have affected the simulation */
////Listeners modified the flight simulation
public static final Warning LISTENERS_AFFECTED = new Other(trans.get("Warning.LISTENERS_AFFECTED"));

34
core/src/net/sf/openrocket/aerodynamics/barrowman/FinSetCalc.java
View File

@ -84,7 +84,9 @@ public class FinSetCalc extends RocketComponentCalc {
public void calculateNonaxialForces(FlightConditions conditions, Transformation transform,
AerodynamicForces forces, WarningSet warnings) {
if (span < 0.001) {
warnings.addAll(geometryWarnings);
if (finArea < MathUtil.EPSILON) {
forces.setCm(0);
forces.setCN(0);
forces.setCNa(0);
@ -97,12 +99,6 @@ public class FinSetCalc extends RocketComponentCalc {
return;
}
if ((bodyRadius > 0) && (thickness > bodyRadius / 2)){
// Add warnings (radius/2 == diameter/4)
warnings.add(Warning.THICK_FIN);
}
warnings.addAll(geometryWarnings);
//////// Calculate CNa. /////////
// One fin without interference (both sub- and supersonic):
@ -241,12 +237,12 @@ public class FinSetCalc extends RocketComponentCalc {
Coordinate[] points = component.getFinPoints();
// Check for jagged edges
// Check geometry
geometryWarnings.clear();
boolean down = false;
for (int i = 1; i < points.length; i++) {
if ((points[i].y > points[i - 1].y + 0.001) && down) {
geometryWarnings.add(Warning.JAGGED_EDGED_FIN);
geometryWarnings.add(Warning.JAGGED_EDGED_FIN, component.toString());
break;
}
if (points[i].y < points[i - 1].y - 0.001) {
@ -254,6 +250,15 @@ public class FinSetCalc extends RocketComponentCalc {
}
}
if (finArea < MathUtil.EPSILON) {
geometryWarnings.add(Warning.ZERO_AREA_FIN, component.toString());
}
if ((bodyRadius > 0) && (thickness > bodyRadius / 2)){
// Add warnings (radius/2 == diameter/4)
geometryWarnings.add(Warning.THICK_FIN, component.toString());
}
// Calculate the chord lead and trail positions and length
Arrays.fill(chordLead, Double.POSITIVE_INFINITY);
@ -365,7 +370,6 @@ public class FinSetCalc extends RocketComponentCalc {
macLead *= dy;
area *= dy;
rollSum *= dy;
macLength /= area;
macSpan /= area;
macLead /= area;
@ -614,6 +618,11 @@ public class FinSetCalc extends RocketComponentCalc {
@Override
public double calculateFrictionCD(FlightConditions conditions, double componentCf, WarningSet warnings) {
// a fin with 0 area contributes no drag
if (finArea < MathUtil.EPSILON) {
return 0.0;
}
double cd = componentCf * (1 + 2 * thickness / macLength) * 2 * finArea / conditions.getRefArea();
return cd;
}
@ -622,6 +631,11 @@ public class FinSetCalc extends RocketComponentCalc {
public double calculatePressureCD(FlightConditions conditions,
double stagnationCD, double baseCD, WarningSet warnings) {
// a fin with 0 area contributes no drag
if (finArea < MathUtil.EPSILON) {
return 0.0;
}
double mach = conditions.getMach();
double cd = 0;