Champs de gradient

Imagine a metal plate heated at the center, creating a temperature distribution across its surface. It can be visualized as a three-dimensional surface, where height represents temperature. The center rises to a peak because the temperature is highest there. Moving away from the center, the temperature gradually drops until the surface becomes flat.

Projecting this surface onto a plane creates contour lines, called isotherms, which connect points at the same temperature.

The gradient is a vector field that maps how this temperature changes across the plate. It points in the direction of the greatest temperature increase and is perpendicular to the isotherms.

At the center, the gradient is zero because the temperature reaches its peak. Farther away, the gradient becomes larger where the temperature changes more sharply, then smaller again as the surface flattens.

Mathematically, the gradient is a vector of partial derivatives of a scalar field, such as temperature. These show how temperature changes in each direction. Its magnitude shows how steep that change is at each point.

This helps identify regions of rapid temperature change that can cause thermal stress and lead to warping or cra