Division 6.7.2 Calculation of the aerodynamic force

The aerodynamic drag shall be calculated using the equation below. If the vehicle is equipped with velocity-dependent movable aerodynamic body parts, the corresponding (C_D × A_f) values shall be applied for the concerned reference speed points.

F_{Aj} = {(C_{D} \times A_{f})}_{j} \times \frac{ρ_{0}}{2} \times \frac{v_{2}^{j}}{{3,6}^{2}}

where:

F_Aj

is the aerodynamic drag measured in the wind tunnel at reference speed j, N;

(C_D × A_f)_j

is the product of the drag coefficient and frontal area at a certain reference speed point j, where applicable, m²;

ρ₀

is the dry air density defined in paragraph 3.2.10. of this Annex, kg/m³;

v_j

is the reference speed j, km/h.