What's the difference between these differential operators?

In summary, the gradient, divergence, and curl are differential operators used in vector calculus to describe and analyze vector fields. They each have different mathematical definitions, with the gradient taking the derivative of a scalar field, the divergence taking the dot product of a vector field, and the curl taking the cross product of a vector field. These operators are related through the Divergence and Curl Theorems, and have real-world applications in fields such as physics, fluid dynamics, and electromagnetism.
  • #1
corona7w
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I'm learning fluid mechanics, and I am confused about the following differential operators. What's the difference between each?
 

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  • #2
the first one is the so called convective derivative. This arises from the fact that in the euler picture we have a velocity field, that is a first order tensor field or vector field, describing the velocity as a function of space and time. Hence velocity or any other vector field doesn't change only by time but by place too. So the differential operator is.

The second one is the variational derivative.

The third one is the usual partial derivative.
 

Related to What's the difference between these differential operators?

What's the difference between gradient, divergence, and curl?

The gradient, divergence, and curl are all differential operators used in vector calculus. They each have different mathematical definitions and physical interpretations, but they all involve taking the derivative of a vector field.

What is the purpose of using these differential operators?

These operators are used to describe and analyze vector fields in a mathematical and physical context. They allow us to calculate important quantities such as rate of change, flux, and rotation of a vector field.

What is the difference between the mathematical definitions of these operators?

The gradient is a vector operator that takes the derivative of a scalar field and results in a vector field. The divergence is a scalar operator that takes the dot product of a vector field and results in a scalar field. The curl is a vector operator that takes the cross product of a vector field and results in a vector field.

How do these operators relate to each other?

The gradient and divergence are related through the Divergence Theorem, which states that the flux of a vector field through a closed surface is equal to the volume integral of the divergence of the field over the enclosed volume. The curl and divergence are related through the Curl Theorem, which states that the circulation of a vector field around a closed loop is equal to the line integral of the field's curl over the loop.

What are some real-world applications of these operators?

The gradient is used in physics to calculate the force of a potential field, such as in the case of gravity or electric fields. The divergence is used in fluid dynamics to describe the flow of a fluid through a given volume. The curl is used in electromagnetism to describe the rotation of a magnetic field and in fluid dynamics to describe the flow of a rotating fluid.

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