Effects of Surface Roughness on Turbulent Transonic Flow Over Circular Arc Bumps in a Channel

Mendonca, Johnson; Sharif, M. A. R.

doi:10.1080/19942060.2010.11015308

Cited by 3 publications

(4 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The separation of the boundary layer inside the supersonic nozzle will generate a separation shock (He et al , 2015). Therefore, large wall divergence or burrs if present inside a supersonic nozzle will generate a complex flow field and its understanding and analysis is quite challenging (Mendonca and Sharif, 2010).…”

Section: Resultsmentioning

confidence: 99%

Numerical assessment of miniaturized cold spray nozzle for additive manufacturing

Nasif

Barron

Balachandar

et al. 2019

HFF

View full text Add to dashboard Cite

Purpose Application of cold spray technology may exhibit significant benefits for the additive manufacturing process, particularly for producing intricate objects. To ascertain the feasibility of such an application, this paper aims to present a numerical investigation of the effect of scaling down a convergent-divergent (de Laval) nozzle, which is typically used in the cold spray industry, on the compressible flow parameters and thermal characteristics. Design/methodology/approach The Navier–Stokes equations and energy equation governing compressible flow are numerically solved using a finite volume method with a coupled solver. The conjugate heat transfer technique is used to couple fluid and solid heat transfer domains and predict the local heat transfer coefficient between the solid and fluid. The use of various RANS turbulence models has also been investigated to quantify the effect of the turbulence model on the simulation. Findings The numerical results reveal that the flow and thermal characteristics are altered as the convergent-divergent nozzle is scaled down. The static pressure and temperature profiles at any section in the nozzle are shifted toward higher values, while the Mach number profile at any section in the nozzle is shifted toward a lower Mach number. The turbulent kinetic energy at the nozzle exit increases with the scaling down of the nozzle geometry. This study also provides convincing evidence that the adiabatic approach is still suitable even though the temperature of the nozzle wall is extremely high, as required for industrial application. Results indicate that it is feasible to use the available capabilities of the cold spray technology for additive manufacturing after scaling down the nozzle. Originality/value The idea of adopting cold spray technology for additive manufacturing is new and innovative. To develop this idea into a viable commercial product, a thorough understanding of the flow physics within a cold spray nozzle is required. The simulation results discussed in this paper demonstrate the effect that scaling down of a convergent-divergent nozzle has on the flow characteristics in the nozzle.

show abstract

Section: Resultsmentioning

confidence: 99%

Numerical assessment of miniaturized cold spray nozzle for additive manufacturing

Nasif

Barron

Balachandar

et al. 2019

HFF

View full text Add to dashboard Cite

show abstract

“…The inability to correctly simulate experimentally observed low-frequency shock oscillations, also notably absent in computational simulations by Oliver et al (2007), was again apparent in the foot of the shock-wave Reynolds stress profiles (Vallet, 2007). Further studies, such as those by Mendonca and Sharif (2010) found that surface roughness should not be ignored in SBLI flows due to the upstream influence and movement of the shock as surface roughness is increased. The RSM model was shown to provide the most accurate results although it was also shown that the k-ω model could provide useful results at a decreased computational cost.…”

Section: Computational Studies Of Sblismentioning

confidence: 96%

Computational study of a complex three-dimensional shock boundary-layer interaction

Katzenberg

MacManus

2015

Engineering Applications of Computational Fluid Mechanics

View full text Add to dashboard Cite

Shock boundary-layer interactions occur in many high-speed aerodynamic flows and they can have a notable impact on design considerations due to the aerodynamic and heat transfer effects. Consequently there is a notable interest in understanding the ability of computational tools to calculate the complex flow fields that can arise in a range of engineering applications. Three-dimensional complex shock boundary layer interaction studies are expensive in both time and computational resources. Although recent studies have begun to focus on the use of more complex computational methods such as large eddy simulations, the aim of this research is to assess the ability of steady Reynolds averaged Navier Stokes turbulence models to simulate the interaction of a planar shock impinging on a cylindrical body under supersonic conditions and to determine if these models have a role to play in engineering design applications. The performance of both eddy viscosity and Reynolds stress models are evaluated relative to an established experimental test case. The impact of Reynolds number and impinging shock strength are also considered. Of the eddy viscosity models it was shown that the Spalart-Allmaras model is unsuitable for this complex interaction and that the k-ε and Reynolds stress methods both gave notably better agreement with the measured surface static pressures. Overall it was considered that the Reynolds stress method was the best model as it also provided better agreement with the measured surface flow topology. It was concluded that, although a steady Reynolds averaged Navier Stokes approach has known limitations for this type of complex interaction, within an engineering context it can also provide useful results when applied appropriately.

show abstract

“…It is based on the results of that a two-dimensional porous medium is simulated. In an article, Nakayama et al [21] proposed equation (7) to calculate the equivalent diameter of different porous media structures.…”

Section: Porous Media To Control Shock and Skin Frictionmentioning

confidence: 99%

“…They found that the separation and impact length and the threedimensional instability structure are observed from blockage 0.5 by changing the Reynolds number from 25 to 3000 and the blockage rate from 0.05 to 0.9 of the channel. Mendonca and Sharif [7] investigated the effects of surface roughness on the supersonic turbulent flow. They conducted experimental studies of the flow passing over a semi-circular obstacle with different heights in a channel and used different solvers such as k-ε and k-ω to investigate the shock phenomenon and skin friction coefficient.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Shock Wave Severity by Porous Media on a Two-Dimensional Obstacle in an Open Channel

Hosseini,

Karimi

2023

Preprint

View full text Add to dashboard Cite

An investigation of compressible flow over two-dimensional obstacles is presented in this paper. When shock waves are formed on surfaces due to compressibility and these shocks interfere with the boundary layer, undesirable effects such as friction, separation, and flow instability occur. To weaken the shock and reduce its effects, various methods have been employed in the past, including surface suction, surface blowing, and vortex generators. Using numerical solutions, the present work attempts to reduce the negative effects of the shock generated by the obstacle by creating porosity on its surface. Numerical methods such as the finite volume method and the Navier-Stokes equations as well as the Spalart-Allmaras model are used. By creating suction and blowing and increasing the cross-sectional area of the flow, porous surfaces reduce the effects of shock. Achieving around 50% porosity on the obstacle weakened the shock and reduced the Mach number after it, according to this paper's results. Also, the area under the skin friction diagram has decreased by about 38% as a result of less interference between the shock and the boundary layer and blowing caused by the porous surface.

show abstract

Effects of Surface Roughness on Turbulent Transonic Flow Over Circular Arc Bumps in a Channel

Cited by 3 publications

References 22 publications

Numerical assessment of miniaturized cold spray nozzle for additive manufacturing

Numerical assessment of miniaturized cold spray nozzle for additive manufacturing

Computational study of a complex three-dimensional shock boundary-layer interaction

Reduction of Shock Wave Severity by Porous Media on a Two-Dimensional Obstacle in an Open Channel

Contact Info

Product

Resources

About