Electromagnetohydrodynamic (EMHD) Flow in a Microchannel with Random Surface Roughness

Ma, Nan; Sun, Yanjun; Jian, Yongjun

doi:10.3390/mi14081617

Cited by 7 publications

(7 citation statements)

References 35 publications

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“…Since the deviation ζ 1 is positive, it is clear that roughness impedes the flow on micropipe, and this effect steadily reinforces as the wave number grows. This conclusion is consistent with the conclusion in reference [22,27]. The deviation ζ 1 approaches to 0 from a negative value with an increase in λ from 0 to 2, which also means that the roughness has a promoting effect on the flow, and the effect weakens with increase in the wave number.…”

Section: Resultssupporting

confidence: 92%

“…ζ 1 is positive, and it approaches 0 with the increase in Ha when the wave number is 3, 5, 10, and 15, which indicates that roughness has an impeding effect on flow, and the effect is gradually weakened with the increase in Ha. This phenomenon also occurs in the electromagnetic flow between microparallel plates with transversely wavy surfaces [22] and electromagnetic flow in microchannels with random surface roughness [27]. In particular, when the wave number is 0 and 1, the deviation is negative, and it approaches 0 with the increase in Ha, which means that roughness has a promoting effect on the flow, and the effect also weakens with the increase in Ha.…”

Section: Resultsmentioning

confidence: 86%

“…Faltas et al [26] investigated the influence of stationary random surfaces on the modified micropolar Brinkman model and particularly evaluated the influence of the corrugations on the pressure gradient and the flow rate. Very recently, by utilizing the perturbation method based upon stationary random function theory, Ma et al [27] studied the effect of small random transverse wall roughness in a parallel plate microchannel on Electromagnetohydrodynamic (EMHD) flow.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Random Roughness on the Electromagnetic Flow in a Micropipe

Wang,

Sun,

Jian

2023

Micromachines

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The features of stationary random processes and the small parameter expansion approach are used in this work to examine the impact of random roughness on the electromagnetic flow in cylindrical micropipes. Utilizing the perturbation method, the analytical solution until second order velocity is achieved. The analytical expression of the roughness function ζ, which is defined as the deviation of the flow rate ratio with roughness to the case having no roughness in a smooth micropipe, is obtained by integrating the spectral density. The roughness function can be taken as the functions of the Hartmann number Ha and the dimensionless wave number λ. Two special corrugated walls of micropipes, i.e., sinusoidal and triangular corrugations, are analyzed in this work. The results reveal that the magnitude of the roughness function rises as the wave number increases for the same Ha. The magnitude of the roughness function decreases as the Ha increases for a prescribed wave number. In the case of sinusoidal corrugation, as the wave number λ increases, the Hartmann number Ha decreases, and the value of ζ increases. We consider the λ ranging from 0 to 15 and the Ha ranging from 0 to 5, with ζ ranging from −2.5 to 27.5. When the λ reaches 15, and the Ha is 0, ζ reaches the maximum value of 27.5. At this point, the impact of the roughness on the flow rate reaches its maximum. Similarly, in the case of triangular corrugation, when the λ reaches 15 and the Ha is 0, ζ reaches the maximum value of 18.7. In addition, the sinusoidal corrugation has a stronger influence on the flow rate under the same values of Ha and λ compared with triangular corrugation.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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The Effect of Random Roughness on the Electromagnetic Flow in a Micropipe

Wang,

Sun,

Jian

2023

Micromachines

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“…Recently, Ma et al [60] investigated the impact of small random transverse wall roughness (sawtooth ripple, rectangular ripple, triangular ripple) on EMHD flow in a microchannel, utilizing the perturbation method based upon stationary random function theory. Most researchers have used domain perturbation [14,16,17,61,62] and lubrication methods [19,63,64] to study flow through a wavy channel, but these approaches have certain limitations.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetohydrodynamic flow through a periodically grooved channel

Dewangan,

Persoons

2024

J. Phys. D: Appl. Phys.

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This paper harnesses the spectral approach to study electromagnetohydrodynamics (EMHD) flow through an undulating 2D microchannel for a Newtonian fluid. The present study aims to investigate EMHD flow through a periodically patterned channel for large values of corrugation amplitude (surface roughness) relative to the channel height, Hartmann number and a wide range of wavelengths. A mathematical model is developed for the hydraulic permeability and the velocity field using the Fourier approach. By imposing a small pattern amplitude constraint, asymptotic analysis was employed to investigate the model presented in the literature. In the present study, hydraulic permeability is shown to strongly depend on the Hartmann number, pattern amplitude and wavelength. The spectral method predicts a monotonic decrease in hydraulic permeability irrespective of pattern amplitude at a small dimensionless wavelength (λ = 1) and Hartmann number (Ha < 1). At large wavelengths (λ > 3), the hydraulic permeability demonstrates an augmentation corresponding to the pattern amplitude. At intermediate wavelength (2.5 < λ < 3), the permeability of the channel firstly decreases and then increases with pattern amplitude. For large Hartmann numbers (Ha >> 1), the prediction from the spectral model exhibits a similar trend as a function of wavelength. Across a range of wavelengths, the spectral model captured the permeability minima for various large Hartmann number values. The spectral model is significantly faster than the finite-element-based numerical simulation, with computational efficiency ranging from 150 to 250 times higher. The existence of a limited pattern amplitude and Hartmann number for small-large wavelength patterns, at which the permeability of the channel is minimized, is one example of a prediction from the spectral model that is beyond the resolution of currently accessible asymptotic theories.

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“…In addition, the EMHD of transverse and longitudinal roughness have been studied [ 31 , 32 ]. Recently, the effect of small-amplitude random lateral wall roughness on EMHD flow in microchannels in parallel plates [ 33 ] and cylindrical [ 34 ] microchannels was studied using the perturbation method of stationary random function theory. Hosham et al [ 35 ] studied the heat and mass transfer effects in EOF based on the viscoplastic Bingham fluid model in complex corrugated microchannels.…”

Section: Introductionmentioning

confidence: 99%

Alternating Current Electroosmotic Flow of Maxwell Fluid in a Parallel Plate Microchannel with Sinusoidal Roughness

Chang,

Zhao,

Buren

et al. 2023

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The EOF of a viscoelastic Maxwell fluid driven by an alternating pressure gradient and electric field in a parallel plate microchannel with sinusoidal roughness has been investigated within the Debye–Hückel approximation based on boundary perturbation expansion and separation of variables. Perturbation solutions were obtained for the potential distribution, the velocity and the mean velocity, and the relation between the mean velocity and the roughness. There are significant differences in the velocity amplitudes of the Newtonian and Maxwell fluids. It is shown here that the velocity distribution of the viscoelastic fluid is significantly affected by the roughness of the walls, which leads to the appearance of fluctuations in the fluid. Also, the velocity is strongly dependent on the phase difference θ of the roughness of the upper and lower plates. As the oscillation Reynolds number ReΩ increases, the velocity profile and the average velocity um(t) of AC EOF oscillate rapidly but the velocity amplitude decreases. The Deborah number De plays a similar role to ReΩ, which makes the AC EOF velocity profile more likely to oscillate. Meanwhile, phase lag χ (representing the phase difference between the electric field and the mean velocity) decreases when G and θ are increased. However, for larger λ (e.g., λ > 3), it almost has no phase lag χ.

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Electromagnetohydrodynamic (EMHD) Flow in a Microchannel with Random Surface Roughness

Cited by 7 publications

References 35 publications

The Effect of Random Roughness on the Electromagnetic Flow in a Micropipe

The Effect of Random Roughness on the Electromagnetic Flow in a Micropipe

Electromagnetohydrodynamic flow through a periodically grooved channel

Alternating Current Electroosmotic Flow of Maxwell Fluid in a Parallel Plate Microchannel with Sinusoidal Roughness

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