Hello, I am new in this field, so maybe my questions will be stupid :) sorry for that :) In the company where I work, they measure flow rates of wastewater using Flow meter (Doppler device). The problem is, that the flow rate is very low, so this device is not submerged completely in the wastewater. Then they put some obstacle at the end of the pipe, that the water level is higher and that this flow meter is submerged in the wastewater. Is it correct to measure the flow rates this way? Does anybody know how to calculate the flow in this circular pipe with obstacle at the bottom of the pipe (the pipe is half closed from the bottom up)? Is it even possible? Does anybody know how to test this flow meter easily on-site, if it shows results correctly? It is not possible to get there huge testing maschines. Thank you very much for help! And sorry for my bad english.