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stream

Set options for the stream plot.

Synopsis:

stream option=value [,option=value, ...]

Arguments:

option

A plot option for the stream plot. See table below.

value

A value associated with the matching option . See table below.

Option

Value

Value Meaning

Default Value

err

real number >= 0.0

A scaled error value. An error of 0.01 means that variations on the order of 1/100 the size of the mesh are filtered out through line reduction. 0.0 means that no variations are filtered.

0.0

density

positive real number

The stream density. This is a scaled parameter. It relates to the "seed point density per unit area", however it is scaled such that a density of 1 results in approximately 200 streams. This is so the results are the same whether the mesh is defined in cm, mm, or any other scale.

1.0

lc

line color

Line color. Color Names A color index may be used in place of a color name.

white

legend

on, off

Whether or not a legend should be displayed with the plot.

on

ls

dash, dot,
dotdash, solid

Line style. Line Styles

solid

lt

1 <= integer <= 4

Number to indicate thickness. 1 is the most thin, and 4 is the thickest.

1

maxsteps

positive integer

Number of integration steps taken per stream.

50

method



euler

rk2

rk4

eulera

rk2a

rk4a

Integration method for computing streams.
1st order Euler integration

2nd order Runge Kutta

4th order Runge Kutta

adaptive step 1st order

adaptive step 2nd order

adaptive step 4th order

rk2

pop

pop

off

step

real number > 0.0

Integration step size. This parameter is scaled according to the size of the mesh compared to the magnitudes of the vectors to allow the step size to give similar quality results in a wide variety of meshes. If using an adaptive method, the specified step is used only as an initial value and will be adjusted according to the curvature of the flow at each point.

0.1

var

variable name

Name of the vector variable. The variable defines pseudocoloring as well. A 3d vector in a 2D mesh is interpreted as {x_component, y_component, colorvar}.

velocity

Description:

Streams work in 2D and 3D meshes. Streams (or streamlines) are curves in a vector field which are tangent to the flow (instantaneous flow). They are generated from a starting "seed" point, and are propagated through a vector field via various methods.

Streams are implemented for all mesh types except non-colinear (curvilinear) 3D. For unstructured meshes, only hexahedral zones are supported at this time.

The stream command is similar to the ribbon command, except that it generates lines (streamlines) while ribbon generates a ribbon (or tube), which is the aggregate of two (or more) streamlines.

Examples:

stream numpoints=3, method="rk2a", maxsteps=40

See Also:

ribbon


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