Postprocessing Group Directory
The user interface pull down OPTIONS:VIEW SOLUTION window offers analysis dependent quantities which can be viewed. Choose the following analysis of interest for details.
The Postprocessing Group consists of the following menu pull-down item:
Postprocessing Group Reserved Extension:
.plt = Files in format for XY plotting generated from the solver.
One window contains all the resources necessary to view the solution of your analysis package. It is assumed you have loaded all the Model Group and Preprocessing Group files before reaching this step. Viewing the solution is invoked by clicking on the File:Open Solution pull-down. This first step loads an analysis solution. You can load multiple solutions by continuing to access this option. A file manager window will appear listing the .pot and .eot files within the current directory. When you invoke this window and no solution file is loaded, a file manager will appear before the postprocessing window appears, forcing you to load a solution. Move through the directories to the one of interest, click on the desired .pot or .eot file and click OK. If an error occurs, ensure the solution file corresponds to the geometry, mesh, and preprocessor files loaded. You can continue to load as many solution files as you wish. Each time you do, the file name is added to the ANALYSIS FILE list.
Once you have loaded all the files you want to, you must first select which analysis file you wish to view. Click on the analysis filename in the ANALYSIS FILE list. The file is first scanned for all the solutions contained in the file. The titles of each of these scanned solutions is displayed in the CURRENT SOLUTION. Clicking on the current solution of choice results in a table becoming visible. Now click on the SELECT DISPLAY TYPE to see all the types of postprocessing displays available. You can now interact with this table in two ways. First by clicking in a cell under the QUANTITY column title. This reveals another list box under the CURRENT SOLUTION box with the quantities which are available to display. Clicking on one of these solutions results in the current active cell in the table being filled with this quantity. The actual quantities are analysis dependent. The second is by clicking in any other column which has a heading defined for that row. This will allow you to edit directly within the cell. Make sure you enter positional values exactly as shown - failure to do so will disable the plotting capability. Also, you may find it helpful to view the models minimum and maximum dimensions using the Options pull-down. When you are finished with all the entries, click on GENERATE PLOT. Clicking on this item results in a plot window appearing or the solution being displayed on the model. For some display types, the plotting surface will be shown on the model. If the displayed surface is correct, click OK. Each type of plot currently available is described below.
Solution files generated from the analysis can be loaded using the FILE:OPEN PLOT option. These files are generally listed as out1.dat to outN.dat and will contain MSTR Technology formatted files generated through choices made in the Options:Apply window. It is recommended you copy any outn.dat files into more meaningful names after each analysis run. Every new analysis will overwrite these files.
Once the solution is loaded, this window is used to generate line, arc, line contour, and color contour plots. You have the ability to put up multiple plots to compare data. This plot windows must be closed individually and will automatically shutdown when the main program is exited. It is also simple to concatenate output data plots to overlay data on the same plots. If you have an interest in doing this, please call our technical support for help. There are many options within the plot window, such as saving the plot for quick recall or inverting the background color. You can also use the FILE:WRITE SOLUTION option to generate a solution file for the current loaded frequency. This ASCII format is location (x,y,z),ux, uy,uz, potential, and pressure. For complex plots, you can toggle between the real, imaginary, magnitude, or phase quantities. The way to do this is shown in the screen grab below. You can also invert the graphics background for printing, save the plot data in MSTR Technology format, send the plot to the printer, and close the window.
Input for the line plot is based on Figure 1.
Hence, to define the line in 3D space, the coordinates of P1, which is X1,Y1,Z1 and P2, which is X2.Y2,Z2 must be entered in the format x,y,z. Note that P1 and P2 are vector from the coordinate center 0,0,0. The number of line points (must be greater than one) is then entered. Input also a title for the plot and labels for the quantity and line axes (not required). Quantity vs. distance along the line is plotted when you click on the right most end of the table in the cell marked "Plot".
Input for the arc plot is based on Figure 2.
P1 and P2 define the plane the arc is in in 3D space and P0 defines the center of the circle. R is the radius of the circle. The value is plotted along the arc from qs to qe at each npts, where theta = 0 is along the P1 axis. The user can also input a title and axis labels. The result is plotted versus magnitude along the arc.
Input for the contour plot is based on Figure 3:
Hence, to define the contour plot, the positions for vectors P0 X0,Y0,Z0, P1 X1,Y1,Z1, and P2 X2,Y2,Z2 must be provided. The position of vector P0 is from the origin 0,0,0. Additionally, the number of points along the P1 axis and the number of points along the P2 axis must be given. The plane is broken up into P0-P1 npts times P0-P2 npts cells. The quantity value is linearly interpolated at the center of each of these cells and plotted on the screen. Hence, increasing the number of cells increases the accuracy of the plot. The user can also specify the title of the plot and how many color/line segments. The color/line segment number refers to the number of color spectrum divisions available. The choice of color or line is toggled by clicking in the appropriate table cell. The choice of 2D or 3D is also toggled by clicking in the cell below the "Display" caption. 2D will result in the solution being displayed on a separate XY plot display, 3D results in the result being displayed directly on the model graphics screen.
Surface contour plots, perhaps the most used of all the plot options, provides the solution on model surfaces. Regions can be turned on or off under the pull-down View/Hide View Surfaces. The calculated solution on all surfaces of all regions displayed will be visible directly on the graphics screen. The user can toggle between line or color contours. You may find this the easiest and quickest way to view the solution after an analysis run.
Certain vector quantities are available as Arrow plots . The field quantity is converted to represent an infinitesimal vector change from the original nodal positions. Hence, the displacement vector will calculate the vector direction of the displacement at a node and vectorially add this to the original nodal position. The resultant vector will be displayed on the model graphics screen. Since this calculated vector requires a time quantity, an wt value must be determined. The magnitude of the arrow can be controlled using the + and – signs. The mathematical representation for the vector quantity is shown below.
There is a vector description similar to the ones above for each component of the solution.
Far-field plots can be generated for any vibrating bodies following the Kirchhoff-Helmholtz Integral Theorem and Green’s Theorem (see, for instance, Acoustics, An Introduction to its Physical Principles and Applications, A.D. Pierce, Acoustical Society of America, 1989, pp 180 - 183). This amounts to calculating the acoustic pressure on a surface which completely encloses the vibrating source and extending the solution to any position in space. Here, the enclosing surface must be a box which is outside of the vibrating source but within the acoustic boundaries. It is necessary for the user to define this box and also the location at which to calculate the far field quantities (the phi/theta plane, the angular value in the plane cut, the start,end location on the value plane, the obs. Dist. in meters or the distance from the center of the box to the observation point, the number of observation points, obs. Pts, the number of points along the box length at which to calculate the pressure field, Pts/wavelength, what the symmetry planes for the box are, Sym x,y,z, the lengths of each side of the box, Box x,y,z, and whether to plot the result on an XY plot or a polar plot). Note that input quantities required are identified in bold print in the preceding discussion. You can also identify the plot by adding Xlabel, Ylabel, or Titles to the display. You must also enter a file name for output information. The following figure will hopefully shed some more light on the necessary inputs.
This is a 2D representation where for 3D, the Z component would be out of the page. The pressure solution is calculated on the Green’s Theorem surface from the finite element solution, and a pressure solution at points outside of the finite element mesh can be derived.
From the Kirchhoff-Helmholtz Integral Equation, the pressure can be calculated at r by knowing both the pressure and pressure gradient on a surface S enclosing the source.
In terms of the finite element solution, you must construct a surface (box) around the entire source but still within the fluid domain. The box should be as close to the source as possible where sufficient accuracy exists to calculate the pressure gradient terms. G above is the free-fluid Green’s function and is given by:
The far-field is calculated at the point 
and R = obs. dist input by the contribution of the pressure and gradient pressure at the input box at point 
. For the axi-symmetric case, 
, so that the calculation becomes independent of phi. It is, however,
necessary to choose a constant phi cut for correct results. Theta and phi determine the plane cuts.
Static plots enable you to see the actual motion in time of the finite element solution. A displacement vector quantity with time is calculated and an animation window is created for viewing the motion. For structural materials, the displacement is derived directly from the finite element solution. For fluid materials, the displacement is calculated from the gradient of the pressure solution. Don’t worry about choosing a scale factor, one is calculated for you on the first run. Subsequent runs allows you to change this scale factor by clicking in the -Scale (decrease) or +Scale (increase) cells. You may also type in the scale factor directly. Choose the number of frames you need for a smooth animation.
Note: far-field plots and static plots are not available in the electrostatic analysis since these are not dependent on frequency (time).
This option will plot the frequency response for a given quantity at a given point X,Y,Z. You will need to input the location and quantity and FEWaves automatically calculates the solution at each frequency for the loaded file. An XY plot is displayed. This option is not valid if the solution contains only one frequency. FEWaves allows you to muliple each solution by either 1.0 or 2*pi*frequency using the Scale cell. This is particularly useful for some postprocessing quantities, such as current for a piezoelectric source or velocity for a pressure solution.