# 3.3.3: Lift and induced drag in wings

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In order to represent the lift curve, a dimensionless coefficient ($$C_L$$) will be used. $$C_L$$ is defined as:

$C_L = \dfrac{L}{\tfrac{1}{2} \rho_{\infty} u_{\infty}^2 S_w},$

which can also be expressed as:

$C_L = \dfrac{L}{\tfrac{1}{2} \rho_{\infty} u_{\infty}^2 S_w} = {1}{\tfrac{1}{2} \rho_{\infty} u_{\infty}^2 S_w} \int_{-b/2}^{b/2} \dfrac{1}{2} \rho_{\infty} u_{\infty}^2 c(y) c_l (y) dy = \dfrac{1}{S_w} \int_{-b/2}^{b/2} c(y) c_l (y) dy.$

Figure 3.24: Induced drag.

Another consequence of the induced velocity is the appearance of a new component of drag (see Figure 3.24), the induced drag. This occurs because the lift is perpendicular to the effective velocity and therefore it has a component in the direction of the freestream (the direction used to measure the aerodynamic drag).

3.3.3: Lift and induced drag in wings is shared under a CC BY-SA 3.0 license and was authored, remixed, and/or curated by Manuel Soler Arnedo via source content that was edited to conform to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.