# LocalResistance

Local Resistance

## Library

HydraulicsByFluidon/Components/Resistors

## Description

The component LocalResistance is a model of a flow resistance that represents the local pressure loss, which is typically calculated with the `Pressure loss coefficient` zeta.

`Diameter` is used for calculation of flow velocity v.

Values of `Pressure loss coefficient` can be found in literature, e. g. in I.E. Idelchik, Handbook of Hydraulic Resistance.

In the following tables standard values for the resistance coefficient `Zeta` are given. It is distinguished between bends (without marked radius of curvature R) and elbows (with considerable radius of curvature R), circular cross-sections are always assumed:

Bend

For bends with distinct radius of curvature R the resistance coefficient `Zeta` changes depending on the angle of curvature phi according to the formula:

From the first table the values for `Zeta` _{90deg} depending on the ratio radius of curvature R to tube diameter d can be taken. The second table specifies values for the factor k depending on the angle of curvature phi (where appropriate interpolation is necessary).

At multiple bends, the following equations can give clues for the calculation of `Zeta`:

Double bend (two bends arranged semicircular):

Room crooked (two bends arranged angular to each other):

Floor crooked (two bends arranged s-shaped):

Elbow

For bends without marked radius of curvature R, `Zeta` can be taken out of the following table and/or can be computed by interpolation:

## Parameters

Name | Label | Description | Data Type | Valid Values |
---|---|---|---|---|

| Zeta | Pressure loss coefficient | Scalar | |

| D | Diameter | Scalar | |

| InputMax | Scalar | ||

| dp | dp | Structure | |

| fixed | Cell of scalars | true | |

| start | Cell of scalars |

Name | Label | Description | Data Type | Valid Values |
---|---|---|---|---|

| forwardFluidProperties | Forward fluid properties between ports | Scalar | true |

Name | Label | Description | Data Type | Valid Values |
---|---|---|---|---|

| Number of Modifiers | Specifies the number of modifiers | Number | |

| Modifiers | Add new modifier | Structure | |

| Variable name | Cell of strings | 'volumeFlowA' | |

| Attribute | Cell of strings | 'start' | |

| Value |

## Ports

Name | Type | Description | IO Type | Number |
---|---|---|---|---|

| implicit | Hydraulic port A | input | 1 |

| implicit | Hydraulic port B | input | 2 |