Applied Fluids Laboratory

Collage of graphs, maps, and photos from the Applied Fluids Laboratory

AFL NEWS

January, 2020: 

Appalachian State Engineering Physics graduate students Brandon Schwartz and Jon Tate are recipients of the 2020 NREIP (Naval Research Enterprise Internship Program) Internship at the Naval Research Laboratory, Stennis Space Center, Mississippi. The internship is administered by the American Society for Engineering Education (ASEE). It is nationally competitive, based on academic achievement, personal statements, recommendations, and career & research interests. It is a 10 week internship that provides an $11,000 stipend. Appalachian's former NREIP awardees include Quinlin Riggs (2018) and Kevin Holway (2012), both from Physics and Astronomy. Brandon and Jon will be working with the Sediment Dynamics section. Here is a link to some of the group's work:

https://www.nrl.navy.mil/news/releases/sediment-research-large-yet-granular-exercise-nrl

Congratulations to Brandon and Jon!

December 20, 2019: Do you have an interest in atmospheric and climate modeling? The AFL is accepting new students! We are looking for students with programming experience (any of these: C, Java, XML, Fortran, Python, MATLAB, ArcGIS) and are familiar with the linux environment.  Please contact Chris Thaxton if you are interested! 

About the AFL

The Applied Fluids Lab at Appalachian State investigates a broad range of topics related to the fluid mechanics of boundary layers and the coupling between fluids and terrestrial surfaces, as well as the development and application of instrumentation and analytical/numerical tools and methodologies. More info: Dr. Chris Thaxton | website.

AFL Information

WRF run request - Our WRF runs are now automated! If you wish for us to run WRF in research or operational mode, please provide the requested information. We will respond within 48 hours.

WRF sample output and parameterization guidance for the Southern Appalachians (APPSAM) can be found here. (Coming Soon). General guidance from the WRF community can be found here.

Related Courses (Thaxton): PHY3150 Atmospheric Physics (text); PHY 5500 Fluid Mechanics (text).

Related Programs: Atmospheric Science Minor [PDF, 480 KB]

Current Projects

Optimizing planetary boundary and surface layer schemes in the WRF model and characterizing turbulence sourcing over the Southern Appalachians.

The Intergovernmental Panel on Climate Change (IPCC), in its latest report, states that climate change will likely lead to more intense and variable weather systems on regional and local scales. The Weather and Research Forecasting model (WRF), developed and supported by a collaborative managed by the National Center for Atmospheric Research (NCAR), is a well-established regional model used by thousands of scholars and forecasters serving in domestic and military capacities throughout the world. To improve the performance of WRF to meet emergent challenges, smaller-scale physical processes that have traditionally been parametrized out of necessity, such as planetary boundary layer (PBL) turbulence and mixing, now require marked improvements in parameterization schemes that are more finely tunable to specific local geographical and climatological conditions. The primary short-term goal of our research team is to optimize PBL parameterization schemes in WRF to better understand and most effectively represent the enhanced turbulence production and resulting dissipation that arise due to the complex terrain and relatively moist climate in the Southern Appalachians.

Theory for Incipient Motion in Oscillatory Flows.

In collaboration with the Naval Research Laboratory, we seek to develop a combined incipient motion formulation for better prediction of sediment mobilization under a range of oscillatory flows. The formulation is based on the role of the fluid shear stresses (e.g., Shields parameter) and pressure gradients (e.g., Sleath parameter; Foster et al., 2006) at the onset of sediment motion. Observations across a range of sediment size and density suggested that incipient motion was induced by the pressure gradients in flows with large accelerations, by the shear stresses in flows with small accelerations, and by the combined effects for intermediate flows. Direct numerical simulations were performed for one set of experiments involving acetate beads. The resulting hydrodynamics and turbulent characteristics were compared with the laboratory experiments. We attempt to close the problem with a theoretical investigation into the force balance on a single grain resting on the bed under prescribed monochromatic oscillatory forcing. The theoretical investigation combines formulae from a variety of sources including empirical and quasi-empirical relations to examine the incipient motion of particles across a wide range of conditions applicable in the marine environment.

Collaborators

UCAR logoWe are a member organization of UCAR! Students, please take advantage of the educational, training, and internship opportunities available.

 

US Naval Research Laboratory logoStudents are encouraged to apply to the Naval Research Enterprise Research Internship Program (NREIP). Through our continued collaborations, we provide opportunities for students to work on leading-edge applied fluids and granular systems research with real-time applications.

 

 

Team Honor's Theses and Capstones

Archer, J.R. Computational fluid modeling of a variable angle fuel injector, App State, 2011

Team Master's Theses

Penders, C. Determining mean grain size in high gradient streams with autocorrelation digital image processing, App State, 2010

Jones, A. Integrated nearshore wave amplitude model for use on portable devices, App State, 2005

Peer-reviewed Publications (students in italics)

Thaxton, C. S., Frank, D., Calantoni, J. March 2018 - In preparation, to be submitted to Journal of Geophys. Res - Oceans. Lagrangian Measurements, Simulation, and Theory for Incipient Motion in Oscillatory Flows.

Thaxton, C.S., W. P. Anderson, Jr., Chuanhui Gu, Borko Stosic, Tatijana Stosic. 2017 - Detrended fluctuation analysis and entropy-complexity causality analysis of temperatures in an urbanized mountain stream. Stoch Environ Res Risk Assess (2017). https://doi.org/10.1007/s00477-017-1434-8

Holway, K, C.S. Thaxton, J. Calantoni. 2012. Application of a simple power law for transport ratio with bimodal distributions of spherical grains under oscillatory forcing, Advances in Water Resources, 48: 47-54

Rice J.S., W.P. Anderson Jr., C.S. Thaxton. 2011. Urbanization influences on stream temperature behavior within low-discharge headwater streams, Hydrological Research Letters (5): 27-31.

Anderson, W.P. Jr., J.L. Anderson, C.S. Thaxton, C.M. Babyak. 2010. Changes in stream temperatures in response to restoration of groundwater discharge and solar heating in a culverted, urban stream, Journal of Hydrology, 393 (3-4): 309-320

Jones, A.F. and C.S. Thaxton. 2008. Integrated Nearshore Wave Amplitude Model for Use on Portable Devices, IEEE SouthestCON 2008, Peer-reviewed conference proceedings, IEEE, Hutnsville, AL, 31-36, DOI 10.1109/SECON.2008.4494249

Calantoni, J. and C.S. Thaxton. 2007. Simple power law for transport ratio with bimodal distributions of coarse sediments under waves. Journal of Geophysical Research, 113, C03003, doi:10.1029/2007JC004237\

Mitasova, H. Thaxton, C.S., Hofierka,, J, McLaughlin, R., Moore, A., Mitas. L. 2007, Path sampling method for modeling overland water flow, sediment transport, and short term terrain evolution in Open Source GIS, Developments in Water Science, Volume 55, Part 2, 2004, Pages 1479-1490

Thaxton, C.S., C.M. Babyak, W. Anderson. J. L. Anderson, W.P. Benner III, J.A. Davis, and C.A. Penders. 2007. Baseline monitoring case study of a high-gradient, urbanized stream - Boone Creek, Boone, NC, 2007 Low Impact Development Conference Proceedings, ASCE. (peer-reviewed - American Society of Civil Engineers, March, 2007)

Thaxton, C.S. and R.A. McLaughlin. 2005. Sediment Capture Effectiveness of Various Baffle Types in a Sediment Retention Pond, Transactions of the ASAE, 48(5): 1795-1802

Thaxton, C.S., Calantoni, J., McLaughlin, R.A. 2004. Hydrodynamic Assessment of Various Types of Baffles in a Sediment Detention Pond, Transactions of the ASAE, 47(3): 741-749.

Thaxton, C.S., Mitasova, H., Mitas, L., McLaughlin, R. 2004. Simulations of distributed watershed erosion, deposition, and terrain evolution using a path sampling Monte Carlo method, ASAE Annual International Meeting 2004; Ottawa, ON; Canada; 1 August 2004 through 4 August 2004; Code 66322. Peer-reviewed: 2069-2082.

Presentations

Thaxton, C.S., N. Sanford, and J. Langston, 2018. Modification of WRF/MPAS PBL Schemes for Northwest Flow Snow (NWFS) Events in the Southern Appalachians, A31K: Boundary Layer Processes and Turbulence, 2018 American Geophysical Union Fall Conference, Wednesday, December 12, 2018, Washington, DC, USA

Thaxton, C.S. and Q. Riggs, 2018. Analysis of seasonally-dependent bias in WRF PBL schemes for the southern Appalachian Mountains. P53 Model Evaluation, WRF/MPAS User's Workshop, NCAR, Boulder Colorado, June 13, 2018

Thaxton, C.S. 2018. Toward Improved Correlations between WRF Model and Remotely-sensed PBL Height Retrievals for the Southern Appalachian Mountains, Ad-Hoc Mixing Layer Height Working Group, April 11, 2018, UMBC (Instrumentation: Ground and Satellite, Modeling)

Thaxton, C. S., J.P. Sherman, I.A. Krintz, Q. Riggs, A. Scher, D. Ross, D. Schelsselman. 2017 AGU Fall Conf., "Optimizing Weather Research and Forecasting model parameterizations for boundary-layer turbulence production and dissipation over the Southern Appalachians," AGU EP43C-1896, New Orleans, LA. (Nov. 14, 2017).

Thaxton, C. S., D. Ross. 2017 WRF Workshop, "Preliminary evaluation of WRF physics options for the Southern Appalachian Mountains," P55 Model Evaluation, Boulder, CO. (June 14, 2017).

Thaxton, C. S., Frank, D., Calantoni, J. 2016 Ocean Sciences, "Lagrangian Measurements, Simulation, and Theory for Incipient Motion in Oscillatory Flows," AGU, New Orleans, LA. (February 25, 2016).

Thaxton, C. S., Frank, D., Calantoni, J. 2016 Ocean Sciences, "Lagrangian Measurements, Simulation, and Theory for Incipient Motion in Oscillatory Flows," AGU, New Orleans, LA. (February 25, 2016).

Thaxton, C. S., Frank, D., Calantoni, J., Simeonov, J., 2015 American Geophysical Union (AGU-Annual Meeting), "Lagrangian Measurements, Simulation, and Theory for Incipient Motion in Oscillatory Flows," AGU, San Francisco, CA. (December 2015).

Thaxton, C.S. 2015. Modeling granular flows in coastal applications, 5 Congreso de Fisica y Matematicas' Universidad de las Americas-Puebla, Cholula, Puebla, MX, April 9, 2015

Thaxton, C.S. and J. Calantoni. 2012. Modeling and experiments for sheet flow transport with bimodal size distributions (Control ID 1487689), AGU Fall Meeting, 3-7 December 2012, San Francisco, California.

Holway, K., C. S. Thaxton, J. Calantoni. 2010. Application of a simple power law for transport ratio with bimodal distributions of spherical grains under oscillatory forcing, Symposium on Two-phase Modelling for Sediment Dynamics in Geophysical Flows, Paris, France, April 26-28, 2011,

Sheremet, A., J. Calantoni, and C.S. Thaxton. 2008. Towards predicting sheet flow sediment transport as a diffusive process. Eos. Trans. AGU 89(53), Fall Meet. Suppl., OS21E-1210.

Calantoni, J. and C. S. Thaxton. 2008. Simple power law for transport ratio with bimodal distributions of coarse sediments under waves, Fourth Gordon Research Conference on Granular and Granular Fluid Flow on June 23, 2008 at Colby College in Waterville, ME

Thaxton, C.S. 2007. Thermal data acquisition and predictive modeling for urbanizing head-water streams in the Southern Appalachians, Invited Lecture, Naval Research Laboratories, Stennis Space Center, MS

Thaxton, C.S., C. Penders, W. Anderson, J. Anderson, C. Babyak, W. Benner, III. 2007. Impacts of Urbanization on Headwater Streams of the New River: How Do We Bring Back the Trout?. 2007 New River Symposium, New River Biota II, May 31 - June 2, 2007, Radford University, Radford, VA.

Anderson, J.L., W.P. Anderson, Jr., C.S. Thaxton, and C.M. Babyak. 2007. Dynamics of episodic temperature variations in an urbanized, high-gradient stream. Paper No. 9-1 in Geological Society of America Abstracts with Programs, Vol. 39(2), p. 17. GSA Southeast Section Meeting, Savannah, GA.

Thaxton, C.S., C.M. Babyak, W. Anderson. J. L. Anderson, W.P. Benner III, J.A. Davis, and C.A. Penders. 2007. Baseline monitoring case study of a high-gradient, urbanized stream - Boone Creek, Boone, NC, 2007 Low Impact Development Conference Proceedings, ASCE. (peer-reviewed - American Society of Civil Engineers, March, 2007)

Thaxton, C.S. 2006. Path sampling Monte Carlo method for watershed-scale terrain evolution in GRASS GIS. Invited lecture, Naval Research Laboratory, Stennis Space Center, MS. May 14, 2006.

Thaxton, C.S. & J. Calantoni. 2006. Vertical sorting and preferrential transport in sheet flow with bimodal size distributions of sediment, Coastal Engineering, 2006: Proceedings of the 30th International Conference on Coastal Engineering (ICCE 2006) 3-8 September, Ed. Jane McKee Smith, World Scientific Publishing, Hackensack, NJ. Vol. 3, pp. 3056-3065.

Penders, C., W. Benner, J. Anderson, C. Thaxton, C. Babyak, W. Anderson. 2006. Case Study: Boone Creek Monitoring Project - Boone, NC, State of North Carolina Undergraduate Research and Creativity Symposium, November 18, 2006, Raleigh, NC.

Thaxton, C.S. and J. Calantoni. 2006. Simple Power Law for Transport Ratio with Bimodal Distribution of Coarse Sediment, N8.00006, 2006 American Physical Society March Meeting, Baltimore, MD

Mitasova, H., C. Thaxton, J. Hofierka, R. McLaughlin, A. Moore, L. Mitas. 2005. Path sampling method for modeling overland water flow, sediment transport, and short term terrain evolution in Open Source GIS. In: C.T. Miller, M.W. Farthing, V.G. Gray, G.F. Pinder eds., Proceedings of the XVth International Conference on Computational Methods in Water Resources (CMWR-XV), June 13-17, 2004, Chapel Hill, NC, USA, Elsevier, pp. 1479-1490.

Thaxton, C.S., Mitasova, H., Mitas, L., McLaughlin, R.A., Landscape-scale Grain Size Dependent Simulations of Erosion and Deposition Using a Path Sampling Method, 204(SW-21), 2004 ASAE/CSAE Annual International Meeting, Ottawa, Canada August 1-4, 2004

McLaughlin, R.A., Thaxton, C.S., Optimal Hydraulic Permeability of Composite Geotextiles as Baffles in a Sedimentation Basin, 218(SW-224), 2004 ASAE/CSAE Annual International Meeting, Ottawa, Canada August 1-4, 2004

Thaxton, C.S. 2004. Path Sampling Monte Carlo Method for Modeling Sediment Transport Processes Over Complex Terrain. 2004. N.C. Sectional Meeting of the American Association of Physics Teachers, Meredith College, Raleigh, NC, 2004.