A Derivative taken with respect to a moving coordinate system, also called a Lagrangian Derivative. It is
given by

where is the Gradient operator and is the Velocity of the fluid. This type of derivative is especially useful in the study of fluid mechanics. When applied to ,

**References**

Batchelor, G K. *An Introduction to Fluid Dynamics.* Cambridge, England: Cambridge
University Press, p. 73, 1977.

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1999-05-26