{\displaystyle {\begin{aligned}c_{\mathrm {d} }&={\dfrac {2F_{\mathrm {d} }}{\rho v^{2}A}}\ \\&=c_{\mathrm {p} }+c_{\mathrm {f} }\\&=\underbrace {{\dfrac {1}{\rho v^{2}A}}\ \displaystyle \int \limits _{S}\mathrm {d} A\,(p-p_{o})\left({\hat {\mathbf {n} }}\cdot {\hat {\mathbf {i} }}\right)} _{c_{\mathrm {p} }}+\underbrace {{\dfrac {1}{\rho v^{2}A}}\ \displaystyle \int \limits _{S}\mathrm {d} A\,\left({\hat {\mathbf {t} }}\cdot {\hat {\mathbf {i} }}\right)T_{w}} _{c_{\mathrm {f} }}\end{aligned}}}