I am using PIV to estimate the tangential velocity of a fluid in an electromagnetic stirrer. This electromagnetic stirrer is an annular channel shape. I obtained as a result, positive velocities and negative velocities. I don’t know what the reason of negative velocities is. What is the algorithm or formula used by the PIV for calculating the tangential velocity?
This is an example
Distance on line [m],Tangent velocity [m/s]
The operation of our prototype is as follows:
We analyse the steady laminar flow of an electrolyte in an open annular channel driven by an azimuthal Lorentz force. An open annular channel, limited laterally by two concentric electrically conducting cylinders and by an insulating wall at the bottom is considered. A low conductivity liquid with particles is contained in the channel, while a uniform magnetic field is applied vertically along the cylinders. A potential difference is applied between the cylindrical electrodes so that an electric current circulates radially within the fluid. The current interacts with the applied magnetic field, giving rise to a Lorentz force that drives the fluid in the azimuthal direction. When the current flows inwardly, the fluid will move in the counter-clockwise direction. Also, vortices appear at a certain voltage.
I need to calculate the maximum velocities at which the fluid moves. For that reason I tried to calculate tangential velocity with the PIV.
would like to contribute to update MATLAB license and keep support PIVlab, but the PAYPAL system does not allow me to make payments from my country. How can I contribute to this? Do you know another way?
2018-05-30 23:06 GMT-07:00 William [via PIVlab - Time-Resolved Digital Particle Image Velocimetry Tool for MATLAB] <[hidden email]>:
Tangential velocity is positive, when the velocity component is from point A towards point B, and negative when from point B towards point A.