Curvilinear Coordinates
Lamé Coefficients
, the infinitesimal displacement vector can be written as,
Define the unit orthogonal basis vectors as,
which??Lamé coefficients.?Following the definition,?we have
and the infinitesimal area vector in the direction of??is,

,
It can also be expressed as,
Compare the two expressions, we obtain the components of the gradient,
Therefore,

For a vector field,
we have from the calculus that,
where the volume??is enclosed by the surface?
. Now we shrink?
?to an infinitesimal cubic volume, such that,
in both sides to?get the divergence of the field,
Combine the gradient and the divergence to get Laplacian,

where the area? is?enclosed by the loop?
. Similarly, we shrink?
?to an infinitesimal area in the direction of?
, then the loop integral goes along the path as follows,

Cancel??in both sides to?get one component of the curl,
Switch the index by??to get another two components,
It can be expressed as a more compact form,
where??is the Levi-Civita symbol.

For Cartesian coordinates?, it is obvious that,
Gradient
Divergence
Laplacian
Curl

For spherical coordinates?
The Lamé coefficients are
Gradient
Divergence
Laplacian
Curl

For spherical coordinates?
The Lamé coefficients are
Gradient
Divergence
Laplacian
Curl