• Dr. Ashok Kumar

To solve flow related problem we have either lagrangian and Eulerian approach. To define a flow, we use either the Lagrangian description or the Eulerian description. In Lagrangian description the picture of fluid flow where each fluid particle carries its own properties such as density, momentum etc. As the particle advance its properties may change in time. The procedure of describing the entire flow by recording the detailed histories of each fluid particle is the langrangian description. The particle properties density, velocity, pressure etc. can be mathematically represented as follow: ρ(t), v(t), Ƥ(t). In Eulerian description rather than following each fluid particle we can record the evolution of the flow properties at every point in the space as time varies. This is the Eulerian description this means that the flow properties at a specified location depend at a specified location & on time. For example The density, velocity, pressure…... can be mathematically represented by v(x,t), Ƥ(x,t), ρ(x,t), Eulerian description is harder to understand (how do we apply conservation law?) For this reason, in fluid mechanics we use mainly the Eulerian description. Whereas the lagrangian description is simple to understand: conservation of mass and Newton’s law apply directly to each fluid particle. However, it is computationally expensive to keep track of the trajectories of all the fluid particle is a flow and therefore the lagrangian description is used only in some numerical simulations.

Eulerian, Lagrangian, Conservation of mass, Newton’s Law, Fluid,

"An Introduction of Lagrangian and Eulerian Approach", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 6, page no.244-246, June 2019, Available :http://www.jetir.org/papers/JETIR1906P38.pdf

"An Introduction of Lagrangian and Eulerian Approach", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 6, page no. pp244-246, June 2019, Available at : http://www.jetir.org/papers/JETIR1906P38.pdf