# Difference between Lagrangian and Eulerian Approach

## Difference between Lagrangian and Eulerian Approach

### Summary:

• In a fluid motion, each fluid particle has its velocity and acceleration at any point in time.
• Velocity and acceleration of a particle may change with time or position.
• Two methods are used in the fluid motion
1. Langrangian Method
2. Eulerian Method

### Comparison Chart

Langrangian Method Eulerian Method
An observer concentrates on the movement of a single fluid particle. An observer concentrates on the fixed point particles.
An observer has to move with the fluid particle to observe its movement. An observer remains stationary and observes changes in the fluid parameters at the fixed point only.
An observer remains stationary and observes changes in the fluid parameters at the fixed point only. The method describes the overall flow characteristics at various points as fluid particles pass.
Not commonly used. Commonly used.

### What is the Lagrangian approach?

• Langrangian method, the observer follows a single fluid particle during its motion and will observe the change in its properties like velocity, acceleration, density, etc

### What is the Eulerian approach?

• Eulerian method, the observer concentrates on a fixed point or a region and will observe the change in velocity, acceleration, density, etc. at that point only.