## acceleration

If where ∂

**u**is the vector velocity, the acceleration may be written as*D***u**/*Dt*, where*D*/*Dt*is the material (or total) derivative. For most purposes in hydrodynamics where Eulerian coordinates are employed, the acceleration is decomposed as follows:**u**/∂*t*is called the local acceleration, and**u**·**∇u**is called the convective acceleration.