1. (a) Given a building of width D (= 100 m) in winds of speed U (= 5 m sec), nondimensionalise the equation of continuity and momentum conservation. Hence, calculate the Reynolds number (Re), state the flow regime, together with characterise the dynamics in terms of force balance and momentum transfer. (10 marks) (b) Use the tailpipe dispersion after a truck to demonstrate the key steps of CFD. (10 marks) (c) Calculate the angular velocity @ of the velocity v=yi+zj+xk (la) (5 marks)