The equation of a paraboloid of length 1 and whose axis is in line with \(\mathrm{x}\) axis is given as \(c(\mathrm{x} / \mathrm{l})=\left(\mathrm{y}^{2}+\mathrm{z}^{2}\right) / a^{2}, 0 \leq x \leq l\) and \(0 \leq y, z \leq a\). Obtain the downwash expression at the surface. If a slender paraboloid undergoes SHM about its nose in a vertical \(y-z\) plane, find the unsteady downwash expression at the surface.