[charles4allme]

Hello,
I would appreciate any input to this problem am facing. Here is the piece of the code.

const volVectorField Uduct = U.db().lookupObject<volVectorField>("U");
const volScalarField Uduct1 = mag(U);
dimensionedScalar Length
(
   "Length",
   dimensionSet(0, 1, 0, 0, 0, 0, 0),
   0.75
);

dimensionedScalar mu
(
   "mu",
   dimensionSet(0, 2, -1, 0, 0, 0, 0),
   1.81e-05
);

const volScalarField Reynold = (Uduct1*Length)/mu;

const scalar first = (3.0/0.4572)/3.7; 

 
const scalar second = Foam::pow(first,1.11);

dimensionedScalar t1
(
   "t1",
   dimensionSet(0, 0, 0, 0, 0, 0, 0),
   6.9
);

const volScalarField third = t1/Reynold;

const volScalarField fourth = 4.518/Reynold;

const volScalarField fifth = fourth*log10(second+third);
const volScalarField frict = -2*log10(first - fifth);
const volScalarField frictfact = pow(1/frict,2);

The error comes from the line of the code

const volScalarField third = t1/Reynold;

I get a

Program received signal SIGFPE, Arithmetic exception.

It seems that the Reynold value is zero. Playing around with the code if I do this

const volScalarField third = Reynold/t1;

, the code runs. What is going on with error cos I assume am making a school boy error in my code or violating the format in OpenFOAM code. Any input will be appreciated.


Thanks.

[akidess]

Can you guarantee your velocity to be non-zero everywhere? Otherwise this is plain division by zero.

[charles4allme]

Hi,

Yeah you are right. I cannot guarantee that. What do you recommend. Do I make use of the velocity at the initial condition to calculate the reynolds number, or do I use an if loop to avoid non-zero velocities.

P.S. I still can't explain why I get a value when I reverse the division I get a value.

const volScalarField third = Reynold/t1;

THanks a lot.

[akidess]

Originally Posted by charles4allme

Hi,
P.S. I still can't explain why I get a value when I reverse the division I get a value.

const volScalarField third = Reynold/t1;

THanks a lot.

These are really very simple basics. t1 is a non-zero constant, so there is no reason why a division would not give a value. What is unclear?

[charles4allme]

Yeah i was just a bit confused. STill figuring basic details of OpenFOAM.

Thanks a lot