Ahot-wire anemometer is a device for measuring fluid velocity in flow systems. it is essentially a fine wire, usually made of platinum, which is heated electrically by passing electrical current through it, and exposed to a flowing fluid (in cross flow configuration) so that the heat generated within the wire is lost by convection to the fluid at steady state. its mean temperature, which can be determined by measuring its electrical resistance, is a function of the fluid velocity (via the convective heat transfer coefficient), fluid temperature, and the rate of heat generation. a. for a fluid of arbitrary prandtl number flowing across a thin wire of diameter d and electrical heat generation rate per unit length ql, develop an expression for the free-stream fluid velocity in terms of the difference between the mean temperature of the wire and the free-stream temperature of the fluid. you may neglect axial conduction within the wire, and consider heat transfer within the wire to be radial.