Turbulent flow characterization near the edge of a steep escarpment

Kilpatrick, Ryan; Hangan, Horia; Siddiqui, Kamran; Lange, Julia; Mann, Jakob

doi:10.1016/j.jweia.2021.104605

Cited by 7 publications

(5 citation statements)

References 31 publications

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“…Furthermore, the altitude difference caused by topographic truncation is most obvious on the west side due to the high-west and low-east topography of the island. The Reynolds numbers based on model height h can be calculated as Re = U h/ν, where U is the streamwise velocity and ν = 1.47 × 10 −5 m 2 /s is the kinematic viscosity of air at 20 • C. The value of Reynolds numbers in this study was approximately 3.0 × 10 5 , which is in the range of 1.7 × 10 5 -4.6 × 10 5 studied by Kilpatrick et al [1]. According to their research, the flow behavior is generally less affected by the Reynolds number.…”

Section: Experimential Set-upmentioning

confidence: 58%

“…According to previous studies [17,[23][24][25], the performance of the transition curve was evaluated by comparing the characteristics of the flow after the transition section with incoming flow, and the less differences observed, the better. However, the studies of Kilpatrick et al [1] and Lange et al [10] highlighted the significant effect of the leading edge geometry of the terrain model on the flow behavior over the Bolund Hill. The implementation of a transition section to smooth the altitude difference between the model edge and the wind tunnel floor may change the leading-edge geometry, but the degree to which the flow is influenced is not completely understood.…”

Section: Transition Sectionsmentioning

confidence: 99%

“…Flow separation and reattachment regions induced by topographies such as ridges, cliffs and escarpments not only lead to misconceptions about flow characteristics but also cause difficulties in wind tunnel testing and numerical simulation. Flow characteristics in a region close to a topographic feature and to what extent the flow is influenced by the terrain geometry are not exactly specific [1]. An in-depth understanding of complex turbulent flows is essential for greatly improving simulation accuracy, especially for numerical simulations including the large eddy simulation (LES) and the unsteady Reynolds-averaged Navier-Stokes (URANS).…”

Section: Introductionmentioning

confidence: 99%

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Effect of Topography Truncation on Experimental Simulation of Flow over Complex Terrain

et al. 2022

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Wind tunnel tests are a commonly used method for studying wind characteristics of complex terrain; but truncation of the terrain model is usually unavoidable and affects the accuracy of the test results. For this reason, the effects of truncated and original terrain models on the simulation of wind characteristics for complex terrain were investigated by considering both nontruncated and truncated models, with the truncated model considering the applicability of two types of transition sections. The results show that the effect of topographic truncation on profiles of mean velocity and turbulence intensity is different for regions and that inclination angle profiles are extremely sensitive to the changing topographic features upwind. In those cases, the spectra of streamwise velocity were overestimated in the low-frequency range but underestimated in the high-frequency range due to topographic truncation. At the same time, the less negative value of the slope of the spectra was found at the inertial subrange. Furthermore, the normalized bandwidth was also influenced by topographic truncation, which was narrowed in windward and leeward regions and broadened in the valley region. We should note that the performance of the transition sections used in this study was quite limited and even resulted in inaccuracies in the simulation.

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Section: Experimential Set-upmentioning

confidence: 58%

Section: Transition Sectionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Topography Truncation on Experimental Simulation of Flow over Complex Terrain

et al. 2022

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“…Separation bubbles originated by different surfaces can interact with each other or downwind obstructions, causing potential flow instabilities, such as a vortex street in the wake [2]. The effects of the shape/geometry of leading edges on the turbulent flow behaviors have been proven [3] to be much more than the influence of the Reynolds number and the inflow profiles. The mixture of separated flows in all wind directions will trigger global flow mechanisms that could lead to the formation of unexpected peak zones and higher values on structural members.…”

Section: Introductionmentioning

confidence: 99%

Exploring the impact of vertically separated flows on wind loads of multi-level structures

Mohammadjani,

Zisis

2023

Front. Phys.

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The complex dynamics of vertically separated flows pose a significant challenge when it comes to assessing the wind loads on multi-level structures, demanding a nuanced understanding of the intricate interplay between atmospheric conditions and architectural designs. Previous studies and wind loading standards provide insufficient guidance for designing wind pressures on multi-level buildings. The behavior of wind around perpendicularly attached surfaces is not quite similar to that of individual flat roofs or walls. When a body is composed of several surfaces with right or oblique angles, the separated flow from surfaces and their interactions will cause complex flow patterns around each surface. A wind tunnel experimental study was carried out on bluff bodies with attached flat plates and other adjacent bluff bodies with different heights to examine the wind-induced pressures on such complex shapes. Mean and peak pressure coefficients were measured to determine the flow interaction patterns and location of localized peak pressures. The results were compared to the Tokyo Polytechnic University Aerodynamic Database of isolated low-rise buildings without eaves. The research findings indicated that there was a noteworthy disparity between the minimum and maximum values and locations of peak pressures on both the wall and roof surfaces of the models used in this study, as compared to the results obtained by the Tokyo Polytechnic University. Moreover, the study conceivably pointed to the difference between the peak negative and positive pressure coefficient locations with the ASCE 7-22 wind loading zones. The peak suction zones were affected by the combined flows at perpendicular faces, and as a result, different wind load zones were obtained dissimilar to those introduced by ASCE 7-22. Wind loading standards may need to be modified to account for the wind pressures on complex building structures with an emphasis on the location of the peak negative pressure zones.

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“…To our knowledge the currently maintained software packages are primarily written in MATLAB, a resource intensive, commercial, closed source software suite. The only remaining currently maintained and free options are, (i) OpenPIV (Liberzon et al, 2021), which is presently transitioning away from MATLAB and towards Python, (ii) JPIV (Vennemann, 2007) written in Java, and (iii) AnaPIV (Nobach, 2016) (Bukhari & Siddiqui, 2008;Chitsaz et al, 2021;Dennis & Siddiqui, 2021Elatar & Siddiqui, 2014;Gajusingh & Siddiqui, 2008;Grieg et al, 2015;Hashemi-Tari et al, 2016;Jaroslawski et al, 2022;Jevnikar & Siddiqui, 2019;Kilpatrick et al, 2021;Marxen, 1998;Shaikh & Siddiqui, 2008;Siddiqui et al, 2001;Siddiqui, 2007;Siddiqui & Loewen, 2007;Sookdeo & Siddiqui, 2010) and it is anticipated that PIVC will continued to be used and developed by the research community.…”

mentioning

confidence: 99%

PIVC: A C/C++ Program for Particle Image Velocimetry Vector Computation

Dennis¹,

Marxen²,

Siddiqui³

2023

JOSS

Self Cite

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Fluid dynamics is an extremely broad area of study where the motion of fluids is investigated and characterized across a wide range of length and time scales. In a majority of practical applications, fluid flow is turbulent in nature, a condition where the fluid motion is highly three-dimensional and stochastic. While the Navier-Stokes equations (governing equations in fluid mechanics) are applicable to all fluid flows, determining a general solution for these equations for turbulent flows is computationally challenging and mathematically impossible. Hence, experimental research is a leading contributor to the advancement of knowledge on fluid dynamics. Experimental research is heavily reliant on the tools and techniques of performing measurements of fluid phenomena. Fluid velocity is one of the fundamental variables and a parameter of interest in fluid mechanics. Hence, knowing the fluid velocity field in time and/or space is often the primary objective in fluid dynamics research. Thus, most of the tools and techniques used in experimental fluid mechanics research are used to measure the fluid velocity in a given flow.

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Turbulent flow characterization near the edge of a steep escarpment

Cited by 7 publications

References 31 publications

Effect of Topography Truncation on Experimental Simulation of Flow over Complex Terrain

Effect of Topography Truncation on Experimental Simulation of Flow over Complex Terrain

Exploring the impact of vertically separated flows on wind loads of multi-level structures

PIVC: A C/C++ Program for Particle Image Velocimetry Vector Computation

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