blockRegNonZeroPower
Extends from Modelica.Blocks.Interfaces.SISO (Single Input Single Output continuous control block).
Information
Block that approximates y=|x|n where 0 < n < 2 so that
- y(0) is not equal to zero.
- dy/dx is bounded and continuous everywhere.
This block replaces y=|x|n in the interval -δ...+δ by a 4-th order polynomial that has the same function value and the first and second derivative at x=± δ.
A typical use of this block is to replace the function for the convective heat transfer coefficient for forced or free convection that is of the form h=c |dT|n for some constant c and exponent 0 < n ≤ 1. By using this block, the original function that has an infinite derivative near zero and that takes on zero at the origin is replaced by a function with a bounded derivative and a non-zero value at the origin. Physically, the region -δ...+δ may be interpreted as the region where heat conduction dominates convection in the boundary layer.
See the package Examples for the graph.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | n | Exponent | |
| Real | delta | 0.01 | Abscissa value where transition occurs |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| RealInput | u (from SISO) | Connector of Real input signal | |
| RealOutput | y (from SISO) | Connector of Real output signal |
Revisions
-
November 2, 2022, by Michael Wetter:
Set minimum and maximum attribute onn, improved assertion and documentation.
This is for Buildings, #3135. -
November 29, 2013 by Marcus Fuchs:
Implementation based on Buildings.Utilities.Math.Functions.regNonZeroPower.