| NSF Org: |
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems |
| Recipient: |
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| Initial Amendment Date: | January 16, 2015 |
| Latest Amendment Date: | January 16, 2015 |
| Award Number: | 1453633 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Ron Joslin
rjoslin@nsf.gov (703)292-7030 CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems ENG Directorate for Engineering |
| Start Date: | March 1, 2015 |
| End Date: | February 29, 2020 (Estimated) |
| Total Intended Award Amount: | $500,000.00 |
| Total Awarded Amount to Date: | $500,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
3112 LEE BUILDING COLLEGE PARK MD US 20742-5100 (301)405-6269 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Mechanical Engineering College Park MD US 20742-5141 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | FD-Fluid Dynamics |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.041 |
ABSTRACT
1453633
Larsson
Even though the majority of flows in industry and in the environment are turbulent, significant gaps exist in our knowledge of their behavior, especially in non-canonical cases (i.e., cases where the flow is not at equilibrium). This is the white space that this CAREER proposal aims to cover -- to develop theory and models for the simulation of compressible, non-equilibrium turbulent flows with Large Eddy Simulations (LES). In addition to the scientific broader impact, educational activities are proposed that are focused on the development of a new classroom software tool that can be used to provide experiential learning to undergraduate and graduate students by offering visual answers to fluid dynamics questions. The software tool would be available to other educators.
The goal of this proposal is to invent new LES models that can accurately simulate the behavior of non-equilibrium turbulent flows close to solid walls (these are known as wall models). This is a critical yet missing element from currently available computational techniques, and the solution to this problem would open up a whole new area of engineering flows that we would be able to predict. The PI proposes to obtain high fidelity simulation data using direct numerical simulations of representative flow cases and then utilize these data to both develop and validate his new models. Successful completion of this project would constitute a step change in our predictive capabilities for non-equilibrium turbulent flows close to solid walls.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The objective of this work was to advance both the science (our ability to describe) and engineering (our ability to make meaningful predictions) of realistic turbulent wall-bounded flows. The work specifically focused on two important special types of wall-bounded flows: compressible flows over non-adiabatic surfaces, and flows with non-zero streamwise pressure gradient.
The project supported multiple different graduate students during parts of their studies, with each producing important research advances that took the form of either new theory or new modeling approaches. The first major product was a new theory for how the mean velocity and turbulent stresses behave near non-adiabatic walls in compressible flow. This paper (Trettel and Larsson, 2016) re-visited the classic work of Van Driest (1951) and presented a new combined theory that, while imperfect and still in need of revisions, constitutes an important step forward. The second major product was the development of grid-adaptation algorithms for turbulence-resolving simulations, published in two separate papers (Toosi and Larsson, 2017 and 2020). These algorithms enable more systematic turbulence-resolving simulations across a very wide range of applications. The final major product was the continuous advancement of modeling techniques for the near-wall turbulence at very high Reynolds numbers in large eddy simulations. This work included a review paper and the co-organization of multiple workshops on the topic, in an attempt to broaden the impact of the work.
In addition to these research activities into computational turbulence, the project also included a component of introducing modern computational methods into the undergraduate curriculum. Specifically, new modules including rudimentary Monte-Carlo simulations were introduced into the junior-level course in statistics in the Mechanical Engineering department. The inclusion of this new material has made the course more relevant to the 21st century, and allows for a more intuitive (for many engineering students) introduction to the statistical concepts of random numbers, confidence intervals, error propagation, and so on. Many of these course modules have now been adopted by the other teachers of this course in the department.
Last Modified: 05/08/2020
Modified by: Johan Larsson
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