Simulation of honeycomb–screen combinations for turbulence management in a subsonic wind tunnel

Kulkarni, Vinayak; Sahoo, Niranjan; Chavan, Sandip D.

doi:10.1016/j.jweia.2010.10.006

Cited by 67 publications

(17 citation statements)

References 21 publications

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“…The honeycomb type of screens, which are generally useful for turbulence reduction if swirl or initially high transverse velocities are present, is discussed in e.g. [5], [10], [11] and [12]. However, the data available on honeycombs is rather limited and mainly given as best practice and empirical laws from experiments.…”

Section: Introductionmentioning

confidence: 99%

Relaminarization of Pipe Flow by Means of 3D-Printed Shaped Honeycombs

Kühnen

Hof

2019

Journal of Fluids Engineering

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Based on a novel control scheme, where a steady modification of the streamwise velocity profile leads to complete relaminarization of initially fully turbulent pipe flow, we investigate the applicability and usefulness of customshaped honeycombs for such control. The custom-shaped honeycombs are used as stationary flow management devices which generate specific modifications of the streamwise velocity profile. Stereoscopic particle image velocimetry and pressure drop measurements are used to investigate and capture the development of the relaminarizing flow downstream these devices. We compare the performance of straight (constant length across the radius of the pipe) honeycombs with custom-shaped ones (variable length across the radius). An attempt is made to find the optimal shape for maximal relaminarization at minimal pressure loss. The maximum attainable Reynolds number for total relaminarization is found to be of the order of 10.000. Consequently the respective reduction in skin friction downstream of the device is almost by a factor of 5. The break-even point, where the additional pressure drop caused by the device is balanced by the savings due to relaminarization and a net gain is obtained, corresponds to a downstream stretch of distances as low as approx. 100 pipe diameters of laminar flow.

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Section: Introductionmentioning

confidence: 99%

Relaminarization of Pipe Flow by Means of 3D-Printed Shaped Honeycombs

Kühnen

Hof

2019

Journal of Fluids Engineering

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“…Honeycomb and screens are not individually modeled, but instead, they A number of studies on free stream turbulence control using honeycomb and screens of various configurations, individually and also their combinations had been carried out [17][18][19][20][21][22][23][24]. A honeycomb with square cells of L/d h of 4-12 and at a downstream of 4d h has turbulence intensity in between 0.15 and 0.2 [19]. The present wind tunnel has a square cell of L/d h of 4, and the first screen is placed at a distance of 4d h from the downstream end of the honeycomb.…”

Section: Numerical Analysismentioning

confidence: 99%

Numerical and experimental investigation of flow in an open-type subsonic wind tunnel

Verma

Baloni

2019

SN Appl. Sci.

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A numerical and experimental investigation of flow, inside the test section of an open-type subsonic wind tunnel, has been incorporated in the present paper. Experimental data are collected at different selected locations along the wind tunnel length and inside the test section. For detail assessment of the spatial variation of flow variables, numerical analysis is carried out. Boundary conditions have a significant influence on the validation of numerical simulation. A novel approach of system curve generation by experimental analysis of wind tunnel is adopted, instead of using the conventional approach of fan-type boundary condition. Mass flow rate and pressure jump obtained by system curve are utilized for inlet and outlet boundary conditions, respectively. Comparison of numerical and experimental flow fields at the test section suggests maximum error of 9.84% in case of area-weighted average wind velocity along the length of the test section, whereas along the height of the test section a maximum error of 7.75% is observed. Keywords Wind tunnel testing • Numerical simulation • Boundary conditions • Honeycomb and screens • System curve • Flow assessment List of symbols L Length of the honeycomb cell d h Hydraulic diameter of the honeycomb cell CFD Computational fluid dynamics VFD Variable frequency drive

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“…In the mathematical modeling of the flow, conservation equations for mass and momentum in cylindrical coordinate the system can be explained as follows (Kulkarni, Sahoo, and Chavan 2011;Hosain and Fdhila 2015) where ρ is the density, μ is component speeds, while r, Φ, and z are cylindrical coordinate parameters. μ is the dynamic viscosity, and P is the pressure.…”

Section: )mentioning

confidence: 99%

Reynolds Number Estimation of Rotameter Based on K-Epsilon Model

Bahrudin

2017

j. widyariset

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Measurement of fluid flow with the aid of a floating element (rotameter) is a simple method used to measure the velocity of the fluid with a better degree of accuracy. However, there is still a tendency for turbulence flows around the floating element (annular area) due to narrowing of the flows area and the geometry shape of the floating element that can reduce the level of the rotameter accuracy. A single phase of turbulent flows through rotameter was estimated using k-epsilon turbulence model. A detailed study has been performed to investigate the influence of turbulence characteristics from the Reynolds Number (Re) as a benchmark for predicting the level of turbulence. The results showed that at the velocity of 800 l/h the level is around 450, which showed that the fluid flow on the rotameter is categorized as turbulence.

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Simulation of honeycomb–screen combinations for turbulence management in a subsonic wind tunnel

Cited by 67 publications

References 21 publications

Relaminarization of Pipe Flow by Means of 3D-Printed Shaped Honeycombs

Relaminarization of Pipe Flow by Means of 3D-Printed Shaped Honeycombs

Numerical and experimental investigation of flow in an open-type subsonic wind tunnel

Reynolds Number Estimation of Rotameter Based on K-Epsilon Model

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