public void calculateClvsAlpha() {
int nValue = 50;
double alphaMin = Math.toRadians(-5);
double alphaMax = Math.toRadians(25);
alphaArray.linspace(alphaMin, alphaMax, nValue);
double alpha;
double q = _clStar - _clAlpha.getEstimatedValue() * _alphaStar.getEstimatedValue();
clAirfoil = new double[nValue];
for (int i = 0; i < nValue; i++) {
alpha = alphaArray.get(i);
if (alpha < _alphaStar.getEstimatedValue()) {
clAirfoil[i] = _clAlpha.getEstimatedValue() * alpha + q;
} else {
double[][] matrixData = {
{
Math.pow(_alphaStall.getEstimatedValue(), 3),
Math.pow(_alphaStall.getEstimatedValue(), 2),
_alphaStall.getEstimatedValue(),
1.0
},
{
3 * Math.pow(_alphaStall.getEstimatedValue(), 2),
2 * _alphaStall.getEstimatedValue(),
1.0,
0.0
},
{
3 * Math.pow(_alphaStar.getEstimatedValue(), 2),
2 * _alphaStar.getEstimatedValue(),
1.0,
0.0
},
{
Math.pow(_alphaStar.getEstimatedValue(), 3),
Math.pow(_alphaStar.getEstimatedValue(), 2),
_alphaStar.getEstimatedValue(),
1.0
}
};
RealMatrix m = MatrixUtils.createRealMatrix(matrixData);
double[] vector = {_clMax, 0, _clAlpha.getEstimatedValue(), _clStar};
double[] solSystem = MyMathUtils.solveLinearSystem(m, vector);
double a = solSystem[0];
double b = solSystem[1];
double c = solSystem[2];
double d = solSystem[3];
clAirfoil[i] = a * Math.pow(alpha, 3) + b * Math.pow(alpha, 2) + c * alpha + d;
}
}
}
/**
* This function plots the airfoil drag polar using a parabolic approssimation.
*
* @author Manuela Ruocco
*/
public void plotPolar() {
System.out.println("\n \n-----------------------------------------------------");
System.out.println("STARTING PLOT AIRFOIL DRAG POLAR");
System.out.println("-----------------------------------------------------");
MyArray alphaArray = new MyArray();
int _numberOfAlpha = 40;
double[] cdArrayPolar = new double[_numberOfAlpha];
double[] clArrayPolar = new double[_numberOfAlpha];
Amount<Angle> alphaActualAmount;
Amount<Angle> alphaStart = Amount.valueOf(toRadians(-6.), SI.RADIAN);
Amount<Angle> alphaEnd = Amount.valueOf(toRadians(12.), SI.RADIAN);
alphaArray.setDouble(
MyArrayUtils.linspace(
alphaStart.getEstimatedValue(), alphaEnd.getEstimatedValue(), _numberOfAlpha));
String folderPathPolar =
MyConfiguration.currentDirectoryString + File.separator + "out" + File.separator;
String subfolderPathPolar =
JPADStaticWriteUtils.createNewFolder(folderPathPolar + "Polar_Airfoil" + File.separator);
for (int i = 0; i < _numberOfAlpha; i++) {
alphaActualAmount = Amount.valueOf(alphaArray.get(i), SI.RADIAN);
clArrayPolar[i] = calculateClAtAlpha(alphaActualAmount.getEstimatedValue());
cdArrayPolar[i] = calculateCdAtAlpha(alphaActualAmount);
}
MyChartToFileUtils.plotNoLegend(
cdArrayPolar,
clArrayPolar,
null,
null,
null,
null,
"Cd",
"Cl",
"",
"",
subfolderPathPolar,
"Polar_Airfoil ");
System.out.println("\n \n-----------------------------------------------------");
System.out.println("DONE");
System.out.println("-----------------------------------------------------");
}
public void plotClvsAlpha(String subfolderPath, String name) {
System.out.println("\n \n-----------------------------------------------------");
System.out.println("STARTING PLOT AIRFOIL CL vs ALPHA CURVE " + name);
System.out.println("-----------------------------------------------------");
MyArray alphaArray = new MyArray();
int _numberOfAlpha = 60;
double[] clArray = new double[_numberOfAlpha];
double[] alphaArrayDeg = new double[_numberOfAlpha];
Amount<Angle> alphaActualAmount;
Amount<Angle> alphaStart = Amount.valueOf(toRadians(-6.), SI.RADIAN);
Amount<Angle> alphaEnd = Amount.valueOf(toRadians(25.0), SI.RADIAN);
alphaArray.setDouble(
MyArrayUtils.linspace(
alphaStart.getEstimatedValue(), alphaEnd.getEstimatedValue(), _numberOfAlpha));
for (int i = 0; i < _numberOfAlpha; i++) {
alphaActualAmount = Amount.valueOf(alphaArray.get(i), SI.RADIAN);
clArray[i] = calculateClAtAlpha(alphaActualAmount.getEstimatedValue());
alphaArrayDeg[i] = alphaActualAmount.to(NonSI.DEGREE_ANGLE).getEstimatedValue();
}
MyChartToFileUtils.plotNoLegend(
alphaArrayDeg,
clArray,
null,
null,
null,
null,
"alpha",
"CL",
"deg",
"",
subfolderPath,
"CL vs alpha Airfoil" + name);
System.out.println("-----------------------------------------------------");
System.out.println("\n DONE");
System.out.println("-----------------------------------------------------");
}
public double calculateClAtAlphaInterp(double alpha) {
double clActual =
MyMathUtils.getInterpolatedValue1DLinear(alphaArray.toArray(), clAirfoil, alpha);
return clActual;
}
