The role of surface texturing on the physics of boundary layer separation over a bump

Beratlis, Nikolaos; Balaras, Elias; Squires, Kyle D.

doi:10.1016/j.ijheatfluidflow.2018.08.006

Cited by 8 publications

(4 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As flow separation occurs on the surface of the body, it becomes natural to explore different ways in which the surface itself could be modified to control it. One approach is to slightly alter the shape of the surface, introducing a particular texturing, such as dimples or spherical beads (Beratlis, Balaras & Squires 2018). Alternatively, the surface can be made slippery (or non-wettable) using the developments in surface chemistry and laser physics (Vorobyev & Guo 2015).…”

Section: Introductionmentioning

confidence: 99%

The effect of slip on the development of flow separation due to a bump in a channel

et al. 2022

View full text Add to dashboard Cite

A numerical study on the effect of surface slip on the flow in a constricted channel is presented, with the aim of exploring the use of surface slip to control flow separation. Our focus is on two-dimensional flow in a channel over a bump, with a fixed aspect ratio, upon which a Robin-type slip boundary condition is imposed. When the channel walls are fully no-slip, such a flow is known to develop a region of separation behind the bump, at sufficiently large Reynolds numbers. The effect of slip on the separation bubble dynamics occurring behind the bump is investigated, for Reynolds numbers $2000$ and $4000$ . It is shown that surface slip (i) attenuates the intensity of separation as it diminishes the minimum of the streamwise velocity within the recirculation region; (ii) delays the onset of flow separation, shifting it downstream, along the bump, and (iii) reduces the dimensions of the separation bubble behind the bump, allowing the flow to reattach sooner. Ultimately, slip inhibits separation, with both the points of separation and reattachment coalescing, for a slip length $\lambda$ of approximately $0.2$ .

show abstract

Section: Introductionmentioning

confidence: 99%

The effect of slip on the development of flow separation due to a bump in a channel

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Obstacle material is also of interest, especially the obstacle surface roughness. [Choi et al (2008); Beratlis et al (2018)] discuss the effects of the surface-roughness on the mean flow past bluff bodies and bumps (respectively). They show that the drag coefficient reaches a minimum value at a critical Reynolds number that decreases with increasing roughness.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the turbulent wake past real seabed elements for velocity variations characterization in the water column.

Ikhennicheu

Germain

Druault

et al. 2019

International Journal of Heat and Fluid Flow

View full text Add to dashboard Cite

show abstract

“…Moreover, the rough profile of the bump was proved to have more advantageous in lubrication and friction reduction compared with crater, and the hardness of the bump was higher than the substrate [23]. Beratlis proved that the resistance of bumps decreased faster than the dimples [24]. Therefore, bumps fabricated in a biomimetic way can achieve self‐cleaning, extreme wetting and wear reduction, which are very important for biological surfaces.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on bumps formation textured by nanosecond laser on Ti6Al4V alloy

Liu

Niu

Lei

et al. 2023

Biosurface and Biotribology

View full text Add to dashboard Cite

The surface properties of biomaterials are the key factors for the success of artificial implants in the body. The creation of patterns on titanium alloys by laser surface texturing techniques can modify the surface to make it multifunctional. The evolution of the surface morphology of Ti6Al4V alloy textured by a nanosecond laser with 1064 nm wavelength in the air is studied. Laser surface texturing treatment is performed on the titanium alloy through different pulse numbers, power, pulse width and scan times to obtain different morphologies. The 2D cross‐section profile shows that the morphology can be divided into three types in the evolution process of various pulse numbers, powers and pulse widths: bump‐shaped, hump‐shaped and crater‐shaped. It is found that the effect of pulse width on morphology mainly depends on power. The effects of laser parameters on the height of bumps and the evolution of morphology are the main research points to analyse the topography evolution. The causes of bumps are also analysed. Energy dispersive spectrometer measures the area irradiated by the laser, and it is found that the oxygen content of the bump is up to 43.1%, which can speculate that the bump is the result of the oxidation reaction.

show abstract

The role of surface texturing on the physics of boundary layer separation over a bump

Cited by 8 publications

References 18 publications

The effect of slip on the development of flow separation due to a bump in a channel

The effect of slip on the development of flow separation due to a bump in a channel

Experimental investigation of the turbulent wake past real seabed elements for velocity variations characterization in the water column.

Experimental study on bumps formation textured by nanosecond laser on Ti6Al4V alloy

Contact Info

Product

Resources

About