The coefficient (lambda=1 / 2 mathrm{~h}^{2}left|partial u_{l} / partial x_{l} ight|) is used to prevent the numerical

The coefficient \(\lambda=1 / 2 \mathrm{~h}^{2}\left|\partial u_{l} / \partial x_{l}\right|\) is used to prevent the numerical oscillations at a shock. Obtain the expression for \(\left|\partial u_{l} / \partial x_{l}\right|\) in terms of the velocity components if \(\mathrm{x}_{l}\) is the direction showing the magnitude of the gradient of a velocity vector in an element.