volume_factor $a_0$ $a_1$ ...$a_n$

This data item defines a polynomial in space in 1D or 2D. The polynomial specifies the cross-sectional area (in 1D) or the thickness (2D) as function of the global $x$ coordinate (1D) or the global $x$,$y$ coordinates (2D). By example, in a 1D solid calculation it can be used to specify varying cross-sectional areas of bars, or in a 1D flow calculation it can be used to specify the cross- sectional area of a channel.

In 1D the polynomial is $a_0 + a_1 x + a_2 x^2 + \ldots$. In 2D the polynomial is $a_0 + a_1 x + a_2 y + a_3 x^2 + a_4 xy + a_5 y^2 + a_6 x^3 + a_7 x^2 y + a_8 x y^2 + a_9 y^3 + \ldots$.

If this record is not specified, the cross-sectional area is 1 (1D) or the thickness is 1 (2D).

See also volume_element_factor.