For blocks only, vertex-centered expansion factor is defined as the ratio of the largest sector volume to the smallest sector volume in the dual mesh control volume around a vertex. For more information on how volume cells are subdivided into sectors to form the dual mesh control volume, see the page on Vertex-Centered Volume.
This metric affects solution accuracy and smoothness in vertex-centered solvers and varies from 1 (good) to ∞ (bad). Large values may indicate an inverted control volume sector in the dual mesh. For this function, the probe renders the vertex and the bounding faces of the dual mesh control volume.
Tip: Use the probe functionality while in the Examine command to visualize the dual mesh control volume when examining any vertex-centered function.