Small Explanation

hello all,

I'm Working on a small project i like to call -The Development of a Thermo-Acoustic Gas Flowmeter. in this project, i'm using a 1.5cm diameter glass U-tube wich will alow the flow of gas within it and a heating wire will heat the gas in the tube. now inorder to measure the flow i have added a mic and speaker at the ends of the tube and with a couple of equasions reguarding frequency generation, the flow will be measured. now my question is one of the equations i cant directly find is an expression which calculates the velocity of gas flow (Q) as a function of temperature. {Q(T)} thnx.