Aerodynamic forces and three-dimensional flow structures in the mean wake of a surface-mounted finite-height square prism

Silva, Bárbara L. da; Chakravarty, Rajat; Sumner, D.; Bergstrom, Donald J.

doi:10.1016/j.ijheatfluidflow.2020.108569

Cited by 36 publications

(29 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Figure 2, it was suggested that these structures have different origins, contrary to the models discussed by Wang et al (2009) [3]. Particularly, da Silva et al (2020) [7] showed that the structures on the upper surface of the cylinder appear to fade, while wake tip vortices are formed because of three-dimensional deflection of the separated flow from the side leading edges of the cylinder. Moreover, there is a spanwise vortex structure named "B t " that is formed by the folding of the separated shear layer from the free end leading edge of the cylinder.…”

Section: Introductionmentioning

confidence: 94%

“…They also reported that both asymmetric and symmetric vortex shedding is observed simultaneously, but the probability of an asymmetrically arranged vortices is higher at the middle height of the object. Most recently, da Silva et al (2020) [7] identified multiple mean wake structures, instead of a single arc-type structure, formed around a wall-mounted square cylinder (small depth-ratio prism) with AR = 3 at Re = 500. As shown in Figure 2, it was suggested that these structures have different origins, contrary to the models discussed by Wang et al (2009) [3].…”

Section: Introductionmentioning

confidence: 99%

“…This newly identified structure has a different origin from the so-called legs of the arc-type structures. da Silva et al (2020) [7] identified that the differences observed compared to the wake model of Wang et al (2009) [3] may be attributed to the transitional nature of the latter wake compared to the mean wake considered in the lower Reynolds number study. These studies, although limited to small depth-ratios, have revealed that, depending on the cylinder aspect ratio and Reynolds number, there are multiple structures formed in the wake with distinct characteristics.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Steady Wake of a Wall-Mounted Rectangular Prism with a Large-Depth-Ratio at Low Reynolds Numbers

2021

View full text Add to dashboard Cite

The wakes of wall-mounted small (square) and large (long) depth-ratio rectangular prisms are numerically studied at Reynolds numbers of 50–250. The large depth-ratio significantly alters the dominance of lateral secondary flow (upwash and downwash) in the wake due to the reattachment of leading-edge separated flow on the surfaces of the prism. This changes the wake topology by varying the entrained flow in the wake region and changing the distribution of vorticity. Thus, the magnitude of vorticity significantly decreases by increasing the prism depth-ratio. Furthermore, the length of the recirculation region and the orientation of near wake flow structures are altered for the larger depth-ratio prism compared to the square prism. Drag and lift coefficients are also affected due to the change of pressure distributions on the rear face of the prism and surface friction force. This behavior is consistently observed for the entire range of Reynolds numbers considered here. The wake size is scaled with Re1/2, whereas drag coefficient scaled with Re−0.3.

show abstract

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Steady Wake of a Wall-Mounted Rectangular Prism with a Large-Depth-Ratio at Low Reynolds Numbers

2021

View full text Add to dashboard Cite

show abstract

“…2009) or a square cylinder (da Silva et al. 2020). These vortices originate from the corners of the front surface owing to partial realignment of the above-mentioned spanwise and wall-normal vorticity generated on the front surface.…”

Section: Discussionmentioning

confidence: 99%

Experimental investigation of the three-dimensional flow structure around a pair of cubes immersed in the inner part of a turbulent channel flow

2021

View full text Add to dashboard Cite

show abstract

“…Existing research investigating flow over surface-mounted objects has focused on characterizing the effect of surface fouling, designing drag-reducing structures, and studying airflow around buildings 6 – 9 . A variety of geometries have been considered, including cubes 10 , 11 , circular cylinders 12 , hemispheres 12 – 14 , pyramids 15 , 16 , cones 17 – 19 , and triangular cylinders 20 , 21 . Most of these studies provide drag and drag-coefficient estimates.…”

Section: Introductionmentioning

confidence: 99%

Sea stars generate downforce to stay attached to surfaces

Hermes

Luhar

2021

Sci Rep

View full text Add to dashboard Cite

Intertidal sea stars often function in environments with extreme hydrodynamic loads that can compromise their ability to remain attached to surfaces. While behavioral responses such as burrowing into sand or sheltering in rock crevices can help minimize hydrodynamic loads, previous work shows that sea stars also alter body shape in response to flow conditions. This morphological plasticity suggests that sea star body shape may play an important hydrodynamic role. In this study, we measured the fluid forces acting on surface-mounted sea star and spherical dome models in water channel tests. All sea star models created downforce, i.e., the fluid pushed the body towards the surface. In contrast, the spherical dome generated lift. We also used Particle Image Velocimetry (PIV) to measure the midplane flow field around the models. Control volume analyses based on the PIV data show that downforce arises because the sea star bodies serve as ramps that divert fluid away from the surface. These observations are further rationalized using force predictions and flow visualizations from numerical simulations. The discovery of downforce generation could explain why sea stars are shaped as they are: the pentaradial geometry aids attachment to surfaces in the presence of high hydrodynamic loads.

show abstract

Aerodynamic forces and three-dimensional flow structures in the mean wake of a surface-mounted finite-height square prism

Cited by 36 publications

References 59 publications

The Steady Wake of a Wall-Mounted Rectangular Prism with a Large-Depth-Ratio at Low Reynolds Numbers

The Steady Wake of a Wall-Mounted Rectangular Prism with a Large-Depth-Ratio at Low Reynolds Numbers

Experimental investigation of the three-dimensional flow structure around a pair of cubes immersed in the inner part of a turbulent channel flow

Sea stars generate downforce to stay attached to surfaces

Contact Info

Product

Resources

About