[uditrao04]

Hello all,
I have a case where I have used the libAcoustics external library to obtain the acoustic performance of a propeller (FFWH). What is the difference between

cleanFreq		100;

and

fftFreq		1024;

and how does it differ from the deltaT and writeInterval that are there in /system/controlDict?

/0/fwhControl

FwhFarasssat1A
{
	type			        FfowcsWilliamsHawkings;
	#include		        "commonSettings";
	patches			("propellerTip");
	interpolationScheme	cell;
	formulationType		Farassat1AFormulation;
	U0			        (.0 .0 .0);
	cleanFreq		        100;
	Blades			8;
	Ufwh			        (.0 .0 .0);
	surfaces
	(
		propellerTip
		{
			type		        patch;
			patches		("propellerTip");
			interpolate	        false;
		}
	);
}

/0/commonSettings

libs		("libAcoustics.so");
log		true;
writeFft	true;
timeStart	0.1;		//change as per case
timeEnd	0.5;		//change as per case
c0		340;
U0		(0 0 0);
dRef		-1;
pName	p;
pInf		101325;
rho		rhoInf;
rhoInf	1.2;
CofR		(0 0 0);
observers
{
	ObserverA
	{
		position	(0 0.25 0.075);
		pRef		2.0e-5;
		fftFreq	1024;
	}
	ObserverB
	{
		position	(0 0.25 0);
		pRef		2.0e-5;
		fftFreq	1024;
	}
	ObserverC
	{
		position	(0 0.25 -0.075);
		pRef		2.0e-5;
		fftFreq	1024;
	}
	ObserverD
	{
		position	(0 0.35 0.075);
		pRef		2.0e-5;
		fftFreq	1024;
	}
	ObserverE
	{
		position	(0 0.35 0);
		pRef		2.0e-5;
		fftFreq	1024;
	}
	ObserverF
	{
		position	(0 0.35 -0.075);
		pRef		2.0e-5;
		fftFreq	1024;
	}
}

Thank you!