The PRM Plume analysis mode is used to display results produced by the PRIME Plume Rise and Building Downwash Model when running BREEZE AERMOD 6. Observe the downwash plumes that are computed by AERMOD whenever the wind is blowing toward a stack in a direction that has non-zero BPIPs.
To use this analysis mode, first run BREEZE AERMOD with the AERMOD_BREEZE_07026.exe (the 07026 designator might be a larger number as future versions of the executable are released by EPA) model and with the Input Menu | Output Options | Other File & Options | Generate Plume Downwash Centerline File option checked. This tells BREEZE AERMOD to generate an Aermod.prm file in the .amz results archive file. After the AERMOD Model Run, launch Downwash Analyst from the Tools Menu. Both the BPIP input data (i.e. the building and stack geometry) and the Aermod.prm data will be loaded into Downwash Analyst. Note: the PRM Plume analysis mode is made available only when an Aermod.prm file is found in the .amz file.
Select the 'PRM Plume' analysis mode to see the AERMOD computed, downwash-influenced plume geometry with the BPIPs Box (Building Profile Input Parameters Box including the Common Tier height, cross-wind structure width, along-wind structure length, and XY offsets from the stack XY center), the Cavity (i.e. near-wake) Boundary, and the Far-Wake Boundary. View this information in either the 3D Display or the side-view Chart display.
| • | Select the mode by clicking on "PRM Plume - Select Stack & Time" in the Mode List. Notice that all the stacks and tiers are shifted vertically down to the bottom plane. This is necessary to demonstrate that the BPIPs produced by BPIPPRM and the Plume Geometry does not contain any information of about relative elevations between stacks and tiers. The PRIME Plume Rise and Building Downwash Model assumes that the elevation of a stack's BPIPs and Plume Geometry are the same as the stack's elevation. |
| • | Select a stack by either clicking on it's name in the Stack List or directly clicking on the 3D stack with the left mouse button. |
| • | Select a date-hour value from the Time List. Use the arrow keys on the keyboard to step up/down through the list to observe the time-sequenced downwash data. Notice how every selected time will display a plume with it's associated BPIPs Box and wake lines. This is because the BREEZE Aermod model only outputs information to the Aermod.prm file when the wind direction is such that a stack has BPIP values and, subsequently, the PRIME Downwash Model is executed. |
| • | Center the stack in the view by positioning the cursor on the stack and clicking the right mouse button. Rotate the view by clicking down with the left mouse button and dragging the mouse left/right and up/down. |
| • | Notice that the wind directions for the plume data is not restricted to 10 degree increments. Notice what happens as the Selected Time, and subsequently the wind direction, changes: |
| 1. | The plume and wake geometry changes due to changes in the BPIPs geometry and the meteorological conditions. |
| 2. | The associated BPIPs Box, for the Selected Time, will shift with the plume direction. The BPIPs box is, in fact, the BPIP values written to the Aermod.prm file by the Prime Plume Rise and Building Downwash Model. Notice how the BPIPs Box will shift slightly from it's original position for Wind Directions that are not increments of 10. This effect is easier to observe using the top-down 2D viewing mode (select '2D' from the display menu or toolbar). |
| • | To automatically rotate the view direction and step through the Time List hit the "Z" key. Hit the 'Z' key again to stop the Automatic Rotation Mode. This 'animation' mode is very useful for observing the PRIME Plumes (i.e. all plumes in the Time List) produced for the Selected Stack. Notice that you can perform all other interactions while in Automatic Rotation Mode. Right mouse click on other objects to reset the center of rotation. Pan the scene by clicking down with the middle mouse button and dragging left/right and up/down. Click on another stack, or click on another stack in the Stack List, to select another stack. Click in the time list to change the Time. Even change the analysis mode by clicking on another selection in the Analysis Mode List. |
| • | Use the Display Menu, or Toolbar Buttons to toggle between the 3D and 2D top-down views. Notice in the top-down view how perspective distortion is removed making it easy to see the boundaries of the BPIPs Boxes and the Plume Sigma Y boundaries. Also, use the Display Menu or Toolbar Buttons to toggle the Axes and Grid display On/Off, and to Reset View (i.e. center the entire scene into view). |
Page url:
http://www.breeze-software.com/prod/aermod-isc/help/index.html?prm___select_stack.htm
