Formula_24933

\[\varepsilon_{i k}=\frac{1}{2}\left(\frac{\partial u_{i}}{\partial x_{k}}+\frac{\partial u_{k}}{\partial x_{i}}+\frac{\partial u_{i}}{\partial x_{i}} \frac{\partial u_{k}}{\partial x_{k}}\right), \quad i, k=1,2,3 .\]