Recent research has pointed out many reasons why the building downwash formulation in AERMOD needs to be updated due to: overly simplified equations for building wake development; equations that do not account for porous or streamlined structures; a discontinuity in the streamline equation; and over predictions when compared to field observations for buildings with a large footprint. Because of these issues, a research study was initiated in late 2016 with an overall objective of improving the building downwash algorithms in PRIME. The research study involved the use of wind tunnel modeling to develop a database of wind speed and turbulence intensity measurements downwind of various rectangular solids and streamlined (i.e., tanks and towers) structures. Based on those measurements, new equations (PRIME2) were developed to better describe the turbulence increase and velocity deficit in building wakes for these structure types. The PRIME2 building wake equations for turbulence intensity increase and velocity deficit were shown to agree better with wind tunnel observations than the current PRIME equations in AERMOD. The new equations were documented in a journal article and were added to AERMOD's PRIME subroutine. A new version of AERMOD was then compiled with the new enhanced turbulence and wind speed equations (PRIME2) for evaluation. The key feature of the PRIME2 equations is that building wake enhanced turbulence decays rapidly back to ambient levels above the top of the building versus the current PRIME theory that has constant enhanced turbulence extending up to the height of the wake. This paper provides details on the implementation of the PRIME2 code into AERMOD, PRIME plume rise enhancements, the field databases used to evaluate PRIME2, and the evaluation of PRIME2 against three field databases. The paper shows that AERMOD with the PRIME2 building downwash equations and other enhancements provides the overall best agreement with field observations.: While AERMOD/PRIME is supposed to provide accurate and unbiased estimates (within a factor of two), recent research has identified several problems with the current building downwash theory in AERMOD and comparisons against field observations have shown significant under and overpredictions. One major problem is that the current theory has the wake effect extending well above the top of the building while new research shows that the wake effect decays rapidly above the top of the building. This could lead AERMOD to underpredict or overpredict ground-level concentrations. Based on recent wind tunnel tests, a new building downwash theory has been developed and documented in a Journal article. This theory has been added to the PRIME building downwash algorithm in AERMOD and is currently included as an Alpha option in AERMOD. This paper evaluates that new theory against field observations and demonstrates that the updated theory provides better agreement with field observations than the current AERMOD. This paper points out that research and development of model building downwash improvements should be an ongoing process to help ensure a "sustainable" future where these improvements can ultimately provide a model with unbiased performance and thereby allow for responsible industrial development. This study has shown that improvements can be made in a rather quick manner and be included as Alpha options in EPA model updates. The next challenge is to transition these options from Alpha to Beta options and then finally to a default status.
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http://dx.doi.org/10.1080/10962247.2022.2120563 | DOI Listing |
Pest Manag Sci
January 2025
Centre for Pesticide Application and Safety, University of Queensland, Brisbane, Australia.
Background: As unmanned aerial spraying systems (UASS) usage grows rapidly worldwide, a critical research study was conducted to optimize the simulation of UASS applications, aiming to enhance pesticide delivery efficiency and reduce environmental impact. The study examined several key aspects for accurate simulation of UASS application with lattice Boltzmann method (LBM). Based on these discussions, the most suitable grid size and simulation parameters were selected to create a robust model for optimizing UASS performance in various pest management scenarios, potentially leading to more targeted and sustainable pest control practices.
View Article and Find Full Text PDFHealth Phys
October 2023
Savannah River National Laboratory, Savannah River Site, Aiken, SC 29808.
During the afternoon of 30 January 2022, the Savannah River Site experienced unusual temperature conditions leading to a fumigation event that triggered safety alarms and caused considerable confusion about the cause of the event. Normally, it is assumed that fumigation events occur early in the day once surface heating has begun. While most fumigation events are related to the breakup of a nocturnal inversion, this event was related to synoptic atmospheric conditions, which provided a more unique scenario that led to the fumigation event.
View Article and Find Full Text PDFJ Air Waste Manag Assoc
December 2022
Air Pollution Control Division, CDPHE, Denver, CO, USA.
Recent research has pointed out many reasons why the building downwash formulation in AERMOD needs to be updated due to: overly simplified equations for building wake development; equations that do not account for porous or streamlined structures; a discontinuity in the streamline equation; and over predictions when compared to field observations for buildings with a large footprint. Because of these issues, a research study was initiated in late 2016 with an overall objective of improving the building downwash algorithms in PRIME. The research study involved the use of wind tunnel modeling to develop a database of wind speed and turbulence intensity measurements downwind of various rectangular solids and streamlined (i.
View Article and Find Full Text PDFJ Exp Biol
May 2021
Department of Biology, Ecology Building, Lund University, SE-223 62 Lund, Sweden.
Hovering insects are divided into two categories: 'normal' hoverers that move the wing symmetrically in a horizontal stroke plane, and those with an inclined stroke plane. Normal hoverers have been suggested to support their weight during both downstroke and upstroke, shedding vortex rings each half-stroke. Insects with an inclined stroke plane should, according to theory, produce flight forces only during downstroke, and only generate one set of vortices.
View Article and Find Full Text PDFAtmos Environ (1994)
August 2020
General Dynamics Information Technology, Research Triangle Park, NC, USA.
The plume dispersion model AERMOD provides an efficient method for modeling ground-level pollutant concentrations in wakes of buildings. In recent years, several studies have shown that the downwash algorithms within AERMOD often perform poorly in certain applications. Some studies have proposed modifications to the downwash algorithm in AERMOD to bring the model closer to representing the underlying physical processes associated with building downwash and closer to more accurately modeling observed pollutant concentrations.
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