[vabishek]

Hello FOAMers,

I am trying to understand the implementation of the rotatingWallVelocity BC. Here is the link to the source code for this BC: http://foam.sourceforge.net/docs/cpp/a05095_source.html.

I am having a hard time trying to figure out the following lines in the code:

 const scalar t = this->db().time().timeOutputValue();
    scalar om = omega_->value(t);

    // Calculate the rotating wall velocity from the specification of the motion
    const vectorField Up
    (
        (-om)*((patch().Cf() - origin_) ^ (axis_/mag(axis_)))
    );

Could someone explain why omega (om), rotation speed in rad/s, is multipled by -1 above.

Thanks,

Abishek

[fumiya]

Hi,

I think that this multiplication is to obey the right-hand rule when om > 0.

Best regards,
Fumiya