This book deals Computational Fluid Dynamics (CFD) with nine chapters which are the use of applied mathematics, physics and computational software to visualize how a liquid flows past and affect objects. CFD is based on the Navier-Stokes equations, describe how the velocity, pressure, temperature and density of a moving fluid are related. In these chapters using numerical and statistical analysis to solve, visualise problems and how the liquid affects as it flows past objects. Physical problems on fluids are solved using partial differential equations with derived boundary conditions which are not available in the literature with the developed Finite Element and Finite Difference software. High Performance Computers are used for calculations required to simulate the interaction of flow past objects. The effect of flow of fluid on objects such as sphere, circular cylinder and trench are described and shown in graphs and tables. To stabilise landslides which are the severe problem in Himalayas, design guidelines for trench drains are developed and described in detail. Results obtained using Finite Element Software and Mathematical models by statistical analysis are compared.