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[#1676] Treat zero-length SymmetricComponent as tube/disk

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This commit is contained in:
SiboVG 2022-09-16 00:50:51 +02:00
parent 7602756dee
commit 55aaea94a3
2 changed files with 26 additions and 9 deletions
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26
core/src/net/sf/openrocket/aerodynamics/BarrowmanCalculator.java
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@ -634,14 +634,19 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
// base drag calculation // base drag calculation
if (c instanceof SymmetricComponent) { if (c instanceof SymmetricComponent) {
SymmetricComponent s = (SymmetricComponent) c; SymmetricComponent s = (SymmetricComponent) c;
double foreRadius = s.getForeRadius();
double aftRadius = s.getAftRadius();
// If length is zero, the component is a disk, i.e. a zero-length tube, so match the fore and aft diameter
if (s.getLength() == 0) {
foreRadius = Math.max(foreRadius, aftRadius);
}
double radius = 0; double radius = 0;
final SymmetricComponent prevComponent = s.getPreviousSymmetricComponent(); final SymmetricComponent prevComponent = s.getPreviousSymmetricComponent();
if (prevComponent != null && configuration.isComponentActive(prevComponent)) if (prevComponent != null && configuration.isComponentActive(prevComponent))
radius = prevComponent.getAftRadius(); radius = prevComponent.getAftRadius();
if (radius < s.getForeRadius()) { if (radius < foreRadius) {
double area = Math.PI * (pow2(s.getForeRadius()) - pow2(radius)); double area = Math.PI * (pow2(foreRadius) - pow2(radius));
cd = stagnation * area / conditions.getRefArea(); cd = stagnation * area / conditions.getRefArea();
total += instanceCount * cd; total += instanceCount * cd;
@ -685,6 +690,13 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
} }
SymmetricComponent s = (SymmetricComponent) c; SymmetricComponent s = (SymmetricComponent) c;
double foreRadius = s.getForeRadius();
double aftRadius = s.getAftRadius();
// If length is zero, the component is a disk, i.e. a zero-length tube, so match the fore and aft diameter
if (s.getLength() == 0) {
final double componentMaxR = Math.max(foreRadius, aftRadius);
foreRadius = aftRadius = componentMaxR;
}
int instanceCount = entry.getValue().size(); int instanceCount = entry.getValue().size();
@ -701,8 +713,8 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
radius = prevComponent.getAftRadius(); radius = prevComponent.getAftRadius();
} }
if (radius > s.getForeRadius()) { if (radius > foreRadius) {
double area = Math.PI * (pow2(radius) - pow2(s.getForeRadius())); double area = Math.PI * (pow2(radius) - pow2(foreRadius));
double cd = base * area / conditions.getRefArea(); double cd = base * area / conditions.getRefArea();
total += instanceCount * cd; total += instanceCount * cd;
if ((forceMap != null) && (prevComponent != null)) { if ((forceMap != null) && (prevComponent != null)) {
@ -712,10 +724,10 @@ public class BarrowmanCalculator extends AbstractAerodynamicCalculator {
// if I'm the last component, set my base CD // if I'm the last component, set my base CD
// note: the iterator *should* serve up the next component.... buuuut .... // note: the iterator *should* serve up the next component.... buuuut ....
// this code has is tested, and there's no compelling reason to change. // this code is tested, and there's no compelling reason to change.
final SymmetricComponent n = s.getNextSymmetricComponent(); final SymmetricComponent n = s.getNextSymmetricComponent();
if ((n == null) || !configuration.isStageActive(n.getStageNumber())) { if ((n == null) || !configuration.isStageActive(n.getStageNumber())) {
double area = Math.PI * pow2(s.getAftRadius()); double area = Math.PI * pow2(aftRadius);
double cd = base * area / conditions.getRefArea(); double cd = base * area / conditions.getRefArea();
total += instanceCount * cd; total += instanceCount * cd;
if (forceMap != null) { if (forceMap != null) {

5
core/src/net/sf/openrocket/aerodynamics/barrowman/SymmetricComponentCalc.java
View File

@ -56,8 +56,13 @@ public class SymmetricComponentCalc extends RocketComponentCalc {
SymmetricComponent component = (SymmetricComponent) c; SymmetricComponent component = (SymmetricComponent) c;
length = component.getLength(); length = component.getLength();
if (length > 0) {
foreRadius = component.getForeRadius(); foreRadius = component.getForeRadius();
aftRadius = component.getAftRadius(); aftRadius = component.getAftRadius();
} else { // If length is zero, the component is a disk, i.e. a zero-length tube, so match the fore and aft diameter
final double componentMaxR = Math.max(component.getForeRadius(), component.getAftRadius());
foreRadius = aftRadius = componentMaxR;
}
fineness = length / (2 * Math.abs(aftRadius - foreRadius)); fineness = length / (2 * Math.abs(aftRadius - foreRadius));
fullVolume = component.getFullVolume(); fullVolume = component.getFullVolume();