injectionpoints

Injection PointsSpecify injection locations and velocity directions for a given injection ds:DRGROUPDRCREATEDRSDUPLICATESeveral sets of injection points may be created for a given injection group, each set being unique to

that group. The information needed to define a set is as follows:

current injection group number, as determined by the Group ID scroll box setting. The

latter may also be set in panel Injection basic arrangement of injection points within the set, as selected from the Set Type menu.

The available options are:(a)Single Point — single point at an arbitrary location in space(b)Line — several uniformly distributed points along a straight line or arc segment(c)Circle — uniformly distributed points within a circular area

(d)Plane — uniformly distributed points within a plane rectangular area(e)Surface — uniformly distributed points lying on the currently displayed mesh surface or

cross-section(f)Boundary Faces — points located at the centroids of a given set of boundary faces(g)Points on Cells/Vertices — multiple points defined relative to mesh cells or injection point position(s) within the mesh, taking into account the selection made

above — see topic Entrance initial direction in which parcels emanating from the injection points will be travelling

— see topic Entrance DirectionSummary data for each set created is displayed in the list at the top of the panel. This consists of set

number, set type and number of injections points in the set. Note that:••Set numbers can be re-used when defining each injection group, i.e. they are not unique

identifiersThe total number of injection points (not parcels) is shown underneath the list box. This is

simply to help you calculate the final number of parcels that will be following set manipulation facilities may be selected from the Action menu:•••Add New Set — create a new set of injection points for the current injection groupModify Set — select an existing set on the list box, change the direction cosines and then

click this button to redefine the entrance directionDelete Set — delete the set selected on the list box

••Duplicate Set — replicate the characteristics of the selected set into a new set. The latter’s

entrance direction data may then be altered using Modify SetPlot Points In Set — display both the injection point location and entrance direction

(shown by a unit vector) for the currently selected set. If the injection point being displayed

represents a spray-generating nozzle, the vector shows both the orientation of the spray cone

axis and the spray All Points — as above, for all currently defined sets•Note that pro-STAR also provides four command-driven facilities for creating and manipulating

parcels:RATE generates multiple, successive sets of parcels from a pre-defined starting set.

Successive changes in droplet diameter and/or initial conditions may be specified for each

new set E scales the initial positions of a range of parcels by given factors in each direction

of the currently active local coordinate RESS eliminates all unused or deleted parcels and renumbers the ones T lists the initial conditions for a given set of parcels

Entrance LocationSpecify the position of a set of injection points. Add New Set must be selected from the Action menu

before carrying out the following steps..User input depends on the option selected in the Set Type menu, as follows: Point — define a single point via one of the Point options:(a)Pick — Pick the required vertex with the screen cursor.(b)Specify — use if the required point is at a vertex location. Enter a value in the Vertex

box. Alternatively, enter the point’s coordinates in the X, Y, Z boxes and in the system

whose number appears in the Point Coordinate System box. If required, click the

adjacent button to select an alternative system from the Coordinate Systems — specify a Number of Points that are uniformly spaced along a straight line segment

(or arc segment if the current Coordinate System number is not Cartesian). The line’s two

end-points, Point1 and Point2, are specified either via option (a) or option (b) described

— specify uniformly distributed points within a circular area. The total number of

points included is calculated from the number of points required in the radial (R) and

circumferential (Theta) directions. Select one of the Circle options to define the circle size

and position:(a)Pick — Use the screen cursor to first pick the centre of the circle and then a point on its

circumference from the plot currently on-screen.(b)Specify — The circle will lie in a plane normal to the z-axis of the Cylindrical

Coordinate System shown on the panel. Click the adjacent button if you wish to select a

different system from the Coordinate Systems dialog. The circle’s centre is located on

the z-axis and at a specified distance Z away from the origin. Enter the Radius value (in

metres) in the box — specify uniformly distributed points within a rectangular area, lying in a plane

normal to the z-axis of the current Cartesian Coordinate System and at a specified distance Z

away from its origin. Click the adjacent button if you wish to select a different system from

the Coordinate Systems dialog. Enter the rectangle’s Minimum and Maximum coordinates

and Number of Points required in the X and Y directions, e — specify uniformly distributed points within a rectangle projected onto the

currently displayed mesh surface or cross-section. Enter the Number of Points required in

the X and Y direction in the text boxes provided. Use the cursor button Select on Plot

Window to define the area by marking two opposite corners. The resulting distribution of

injection points is mapped onto the surface displayed in the main pro-STAR ry Faces — specify points located at the centroids of a given set of boundary faces.

The latter may be either the current set (option Bset) or all boundaries in the current region

(option Region Boundary), where the required region is selected from the panel’s scroll

on Cells/Vertices — specify points at arbitrary locations within the mesh, by

selecting them individually with the screen cursor. This is done by first choosing one of the

following options from the Action menu:(a)Add Vertex — use the cursor button Select on Plot Window to select an existing vertex

from the screen plot. The vertex is added to the Select Starting Locations scroll list. Use

the Locate Items menu to control the way the cursor picks a vertex from the screen plot.

(b)Create & Add Vertex — use the cursor button Select on Plot Window to create a new

vertex at an arbitrary location within the mesh before adding it to the Select Starting

Locations list. Use the options to control the precise positioning of the new ation on the current set of points is displayed in the scroll list and includes the vertex

number and coordinates. Note that:i)Points can be deleted from the list by first selecting them and then clicking Clear

)Clear All deletes y, click Apply to confirm your input and create the set.

Entrance DirectionSpecify the injection direction for parcels emanating from the current set of injection input depends on the option selected in the Set Type menu, as follows: options except Points on Cells/Vertices — type in the Injection Direction Coordinate

System in the text box provided or select a system from the Coordinate System dialog by

clicking the adjacent s Single Point, Line, Points on Cells/Vertices — enter the three components DX,

DY, DZ of a unit vector aligned along the injection direction. These are defined in the

coordinate system shown in the Injection Direction Coordinate System Circle — use the Entrance Direction Vector menu to choose between the following

two options:(a)Constant — the direction is specified via the three components of a unit vector in the

current coordinate system, as for (2) above.(b)Relative — parcels are injected at a constant entrance Angle, measured relative to the

normal to the plane (or surface) on which the circle lies. The direction varies according

to the injection point’s position on that s Plane, Surface, Boundary Faces — use the Entrance Direction Vector menu to

choose between the following two options:(a)Constant — the direction is specified via the three components of a unit vector in the

current coordinate system, as for (2) above.(b)Normal — the direction is normal to the plane/surface/boundary face in question

If injection point locations are defined without proper direction data, simply select the set in question

in the panel’s scroll list, specify the direction as described above and then select Modify Set in the

Action menu to confirm your input.