Numerical simulation of helical flow in a cylindrical channel

Numerical simulation of the helical flow in a cylindrical channel with diverter was carried out using open-source software OpenFOAM Extend 4.0. The velocity, vorticity and helicity density distributions were analyzed. It was shown that azimithal contribution of helicity is negative near the wall and positive in the center. In opposite axial helicity contribution is negative in the center and positive near the wall. Analysis of helicity of non-axisymmetric part of the flow showed that it has substantial values near the diverter but than rapidly decreases with y (axial coordinate) and further downstream it can be neglected. Dependencies of integrated values of azimuthal H-phi and axial H-y contributions of helicity density on y show a remarkable quantitative similarity. It was found that integral values of H-phi and H-y are negative for all y. Magnitudes of H-phi and H-y decrease after the diverter up to y approximate to 70 mm and after that monotonically increase. The flow behind the diverter is characterized by substantial amount of helicity and can be used as a helicity generator.