Читать книгу Analysis and Control of Electric Drives - Ned Mohan - Страница 46

The aerodynamic drag force in automobiles can be estimated as f_L = 0.046 C_w A u ², where the coefficient 0.046 has the appropriate units, the drag force is in N, C_w is the drag coefficient (a unit‐less quantity), A is the vehicle cross‐sectional area in m², and u is the sum of the vehicle speed and headwind in km/h [1]. If A = 1.8 m² for two vehicles with C_w = 0.3 and C_w = 0.5, respectively, calculate the drag force and the power required to overcome it at the speeds of 50 and 100 km/h.