Yaw and Pitch angle for gasturbflow

Haloejsa

Dear All, I have to model the flow after a gas turbine and I have received measured data. The data is yaw and pitch angle and absolute velocity. I can guess so far that the absolute velocity must be the total velocity, but I don't have any idea about the yaw and pitch angle. Are they a common term for gas turbine people, if so could someone please give a definition. I have guessed several definitions but the flow profile still looks odd.

Thanks in advance Jan