Browsing by Author "Aikens, Kurt"
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- ItemA Test of the Validity of Inviscid Wall-Modeled LES(Houghton College, 2015-11-22) Redman, Andrew; Craft, Kyle; Aikens, KurtComputational expense is one of the main deterrents to more widespread use of large eddy simulations (LES). As such, it is important to reduce computational costs whenever possible. In this vein, it may be reasonable to assume that high Reynolds numbers flows with turbulent boundary layers and inviscid when using a wall model. This assumption relies on the grid being too coarse to resolve either the viscous length scales in the outer flow or those near near walls. We are not aware of other studies that have suggested or examined the validity of this approach. The inviscid wall-modeled LES assumption is tested here for supersonic flow over a flat plate on three differennt grids. Inviscid and viscous results are compared to those of another wall-modelled LES as well as experimental data-the results appear promising. Furthermore, the inviscid assumption reduces simulation costs by about 25% and 39% for supersonic and subsonic flows, respectively, with the current LES aapplication. Reccommendations are presented as are future areas of research.68th Annual Meeting of the APS Division of Fluid Dynamics, Boston, MA, Nov. 22-24, 2015; XXXV Annual Rochester Symposium for Physics Students, University of Rochester, Rochester, NY., April 2, 2016.
- ItemConstruction of a Low-Speed Closed-Return Wind Tunnel(Houghton College, 2019-03-30) Durbin, Jonathan; Aikens, KurtXXXVIII Annual Rochester Symposium for Physics Students, University of Rochester (Rochester, NY).
- ItemDesign and Construction of a Deposition Chamber for Thin Metal Films Research(Houghton College, 2009-05-06) Aikens, KurtA high vacuum deposition chamber is being built at Houghton College for the production and study of thin metal films. Up to four electron-beam heated crucibles will be used to evaporate metals whose evaporate is adsorbed onto a substrate, forming a film. Evaporation rates may be monitored via crucible temperatures or direct measurement of the ionized flux. The chamber will feature a computer-controlled shield enabling the deposition of samples with varying thickness gradients and an ion gun for substrate cleaning and ion beam assisted deposition (IBAD). The history and theory of vacuum and deposition technologies are discussed. Future plans and current progress are also presented.
- ItemDesign and Construction of a Deposition Chamber for Thin Metal Films Research(Houghton College, 2008-04-05) Aikens, Kurt; Hoffman, BrandonA high vacuum deposition chamber is being built at Houghton College for studies of thin metal films. Metal atoms evaporated via an electron beam will contact a silicon wafer at near normal incidence, growing a uniform thin film. An ion mill will be constructed for cleaning the silicon wafers and for ion beam assisted deposition (IBAD). A computer-controlled shield will enable deposition of samples of varying thickness.XXVII Annual Rochester Symposium for Physics Students, University of Rochester, Rochester, NY., April 5, 2008.
- ItemDesign and Construction of a Deposition Chamber for Thin Metal Films Research(Houghton College, 2009-04-04) Aikens, Kurt; Hoffman, BrandonXXVIII Annual Rochester Symposium for Physics Students, U.S. Military Academy at West Point (West Point, NY).
- ItemDesign, Construction, and Testing of the Return Portion of a Closed-Return Wind Tunnel(Houghton College, 2020-04-21) Langa, Bernardo Jr.; Aikens, KurtHoughton College Physics Research Symposium (Online).
- Item“Impeller Mixing Simulations of Transitional Flow(Houghton College, 2019-03-30) Kratz, Josiah; Malone, Jared; Aikens, KurtImpellers have a wide variety of industrial applications and are utilized in many industries. They are an integral part of the mixing process. The potential for operating inefficiencies causing large financial losses motivate the field to develop processes with which to accurately model the mixing process. Computational fluid dynamics (CFD) is a powerful tool for analyzing mixing scenarios. Multiple methodologies were used to simulate impeller mixing at different operating conditions. Results were compared to experimental data provided by SPX Flow to assess the validity of these methodologies. It is hoped that these comparisons will lead to a proper methodology for simulating impellers operating in the transitional flow regime, which has notoriously been a challenging task. Presently, the mixing problem is being evaluated in a baffled tank with an A200 impeller at various Reynolds numbers. Power number and mixing time predictions are calculated and compared with available data and correlations.XXXVIII Annual Rochester Symposium for Physics Students, University of Rochester, March 30, 2019.
- ItemMaximizing Corner Efficiency for a Low-Speed Closed-Return Wind Tunnel(Houghton College, 2018-04-07) Eager, Daniel; Aikens, KurtXXXVII Annual Rochester Symposium for Physics Students, SUNY Brockport (Brockport, NY).
- ItemNozzle Design for a Small, Low-Speed, Closed-Return Wind Tunnel(Houghton College, 2018-04-07) Martin, Jeremy; Aikens, KurtXXXVII Annual Rochester Symposium for Physics Students, SUNY Brockport (Brockport, NY).
- ItemProgress Towards an LES Wall Model Including Unresolved Roughness(Houghton College, 2015-11-22) Craft, Kyle; Redman, Andrew; Aikens, KurtWall models used in large eddy simulations(LES) are often based on the oriesforhy draulically smooth walls. While this is reasonable for many applications, there are also many where the impact of surface roughness is important. A previously developed wall model has been used primarily for jet engine aeroacoustics. However, jet simulations have not accurately captured thick initial shear layers found in some experimental data. This may partly be due to nozzle wall roughness used in the experiments to promote turbulent boundary layers. As a result, the wall model is extended to include the effects of unresolved wall roughness through appropriate alterations to the log-law. The methodology is tested for incompressible flat plate boundary layers with different surface roughness. Correct trends are noted for the impact of surface roughness on the velocity profile. However, velocity deficit profiles and the Reynolds stresses do not collapse as well as expected for higher roughness. Possible reasons for the discrepancies as well as future work are presented.68th Annual Meeting of the APS Division of Fluid Dynamics, Boston, MA, Nov. 22-24, 2015; XXXV Annual Rochester Symposium for Physics Students, University of Rochester, Rochester, NY., April 2, 2016.
- ItemSimulating Impeller Mixing Under Various Conditions(Houghton College, 2018-04-07) Phillips, Heather; Durbin, Jonathan; Aikens, KurtImpeller mixing, owing to its widespread industrial use, can cause significant financial losses if not performed efficiently. Computational fluid dynamics (CFD) can greatly aid in the design of mixing systems when it is sufficiently accurate. For this work, fluid mixing is performed using an A200 impeller operating in a baffled tank. Simulations were performed of this setup using different approaches and under various operating conditions. Results are compared to available experimental data to guide the development of an overall ANSYS Fluent mixing prediction methodology. Qualitative trends of the experimental data were successfully predicted and discrepancies were generally less than 20%. Overall, the methodology appears promising and will be used in the future to make more detailed predictions of mixing when the flow is transitional – a historically challenging task. Additionally, the approximate solution approach utilized here will be further examined in an attempt to reduce discrepancies between the simulation results and those of the experiments.XXXVII Annual Rochester Symposium for Physics Students, SUNY Brockport, Brockport, NY., April 7, 2018.
- ItemThe Design and Construction of a General Purpose Low-Speed Wind Tunnel(Houghton College, 2017-04-01) Jaramillo, Jonathan; Aikens, KurtXXXVI Annual Rochester Symposium for Physics Students, University of Rochester (Rochester, NY).
- ItemValidation of the gFR Computational Fluid Dynamics Methodology(Houghton College, 2017-04-01) Eager, Daniel; Aikens, KurtThere is a current demand in computational fluid dynamics (CFD) for higher-order solvers that can simulate fluid flows using unstructured grids. Such software would allow for highlyaccurate simulations of complex and industrially-relevant geometries. To help meet these needs, a new code, gFR, is being developed by researchers at the NASA Glenn Research Center. It is based on the flux reconstruction (FR) methods of H.T. Huynh, which are used to solve the three-dimensional Navier-Stokes equations. The methodology is capable of performing efficient and accurate large eddy simulations (LES) and, depending on userspecified choices, can recover many popular high-order methods including the discontinuous Galerkin, spectral difference, and spectral volume methods. Runge-Kutta methods are used to advance the governing equations in time. While gFR has many theoretical advantages, it had only been tested on two problems prior to the present work: a two-dimensional inviscid vortex and the Taylor-Green vortex problem. The present study at Houghton College includes tests of laminar flow over a flat plate as well as laminar channel flow over a backward-facing step. Preliminary results are shown for the two test cases and compared with corresponding experimental and theoretical results. Challenges are described and possible future work is outlined.XXXVI Annual Rochester Symposium for Physics Students, University of Rochester, Rochester, NY., April 1, 2017.