Deformation of an elastic capsule in a microfluidic T-junction: settling shape and moduli determination

Koolivand, Abdollah; Dimitrakopoulos, P.

doi:10.1007/s10404-017-1923-6

Cited by 13 publications

(9 citation statements)

References 42 publications

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“…[109] Earlier researchers do not know whether the burning wave propagates through the white dwarf as a supersonic detonation or as a subsonic deflagration. [108][109][110][111][112][113][114][115][116][117][118][119][120][121][122]. Herein, we provide the proof of the concept of the Sanal flow choking and streamtube flow choking causing the sharp pressure spike due to shock wave formation.…”

Section: Discussionmentioning

confidence: 80%

The Physics of Detonation Chemistry: A Radical Theory in Predicting the Deflagration to Detonation Transition and Environmental Explosions

Kumar¹,

Chandrasekaran²,

Sankar³

et al. 2021

Preprint

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The theoretical finding of the Sanal-flow-choking [PMCID: PMC7267099] and streamtube flow choking (V.R.Sanal Kumar et al., Physics of Fluids, Vol.33, No.3, 2021, DOI: 10.1063/5.0040440) are methodological advancements in predicting the deflagration-to-detonation-transition (DDT) in the real-world-fluid flows (continuum/non-continuum) with credibility.[1,2] Herein, we provide a proof of the concept of the Sanal-flow-choking and streamtube-flow-choking causing DDT in wall-bounded and free-external flows. Once the streamlines compacted, the considerable pressure difference attains inside the streamtube and the flow gets accelerated to the constricted region for satisfying the continuity condition set by the conservation law of nature. If the shape of the streamtube in the internal/external flow is similar to the convergent-divergent (CD) duct the phenomenon of the Sanal-flow-choking and supersonic flow development occurs at a critical-total-to-static pressure ratio (CPR) in yocto to yotta scale systems and beyond, which leads to shock wave generation or detonation as the case may me. At the lower critical detonation or hemorrhage index, the CPR of the reacting flow and the critical blood-pressure-ratio (BPR) of the subjects (human being/animal) are unique functions of the heat-capacity-ratio (HCR) of the evolved gas in the CD duct (V.R.Sanal Kumar et al., Global Challenges, Wiley Publication, January 2021, DOI: 10.1002/gch2.202000076, PMCID: PMC7933821; Sanal Kumar V.R et al. Stroke, Vol. 52, Issue Suppl_11 March 2021, doi.org/10.1161/str.52.suppl_1.P804). In silico results are presented herein to establish the proof of the concept of the Sanal-flow-choking and streamtube-flow-choking causing shock-wave/detonation in diabatic flow systems and asymptomatic-hemorrhagic-stroke in biological systems. The physics of detonation chemistry presented herein sheds light for exploring environmental and supernova explosions.[107] In silico results reported herein provide an authentic answer to many unresolved research questions in Physics in general and aerospace, mechanical, biological, chemical, energy, environmental, nano and material sciences in particular.

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Section: Discussionmentioning

confidence: 80%

The Physics of Detonation Chemistry: A Radical Theory in Predicting the Deflagration to Detonation Transition and Environmental Explosions

Kumar¹,

Chandrasekaran²,

Sankar³

et al. 2021

Preprint

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“…We emphasize that in this section we presented a detailed description of the physical problem and our mathematical methodology under periodic conditions for the better understanding of the present study but also for future reference. More details on our spectral boundary algorithm and our studies on capsule dynamics in microfluidic flows can be found in our recent publications, e.g., [15,17,41,44,48].…”

Section: Computational Methodologymentioning

confidence: 99%

“…During the last decades the research interest has been mainly focused on the capsule dynamics in cylindrical or rectangular channels, e.g., [12,[14][15][16][17]. However, channels with asymmetric cross-sections may also be desirable especially for the lateral migration of capsules which plays a significant role in industrial and physiological processes involving drug delivery, cell sorting and cell characterization [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Motion of an Elastic Capsule in a Trapezoidal Microchannel under Stokes Flow Conditions

Koolivand

Dimitrakopoulos

2020

Polymers

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Even though the research interest in the last decades has been mainly focused on the capsule dynamics in cylindrical or rectangular ducts, channels with asymmetric cross-sections may also be desirable especially for capsule migration and sorting. Therefore, in the present study we investigate computationally the motion of an elastic spherical capsule in an isosceles trapezoidal microchannel at low and moderate flow rates under the Stokes regime. The steady-state capsule location is quite close to the location where the single-phase velocity of the surrounding fluid is maximized. Owing to the asymmetry of the trapezoidal channel, the capsule’s steady-state shape is asymmetric while its membrane slowly tank-treads. In addition, our investigation reveals that tall trapezoidal channels with low base ratios produce significant off-center migration for large capsules compared to that for smaller capsules for a given channel length. Thus, we propose a microdevice for the sorting of artificial and physiological capsules based on their size, by utilizing tall trapezoidal microchannels with low base ratios. The proposed sorting microdevice can be readily produced via glass fabrication or as a microfluidic device via micromilling, while the required flow conditions do not cause membrane rupture.

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“…The capsule is typically modelled as a liquid droplet enclosed by a thin, hyperelastic membrane. Zhu & Brandt (2015) considered the flow past a right-angled corner, while Koolivand & Dimitrakopoulos (2017) examined the deformation of a capsule trapped at the stagnation point of a T-junction, with both geometries offering new measurement methods of the elastic properties of the membrane based on large deformations of the capsule. Following the two-dimensional numerical model of Woolfenden & Blyth (2011), the motion of capsules through branched tubes has recently been addressed in three dimensions by Wang et al (2016Wang et al ( , 2018, who focused on the path selection of the capsule in the presence of inertia with a view to designing an enrichment device.…”

Section: Introductionmentioning

confidence: 99%

Deformation and sorting of capsules in a T-junction

2019

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We study experimentally the motion and deformation of individual capsules transported by a constant volume-flux flow of low Reynolds number, through the T-junction of a channel with rectangular cross-section. We use millimetric ovalbumin-alginate capsules which we manufacture and characterise independently of the flow experiment. Centred capsules travel at constant velocity down the straight channel leading to the T-junction where they decelerate and expand in the spanwise direction before turning into one of the two identical daughter channels. There, non-inertial lift forces act to re-centre them and relax their shape until they reach a steady state of propagation. We find that the dynamics of fixed-size capsules within our channel geometry are governed by a capillary number Ca defined as the ratio of viscous shear forces to elastic restoring forces. We quantify the elastic forces by statically compressing the capsule to 50% of its initial diameter between parallel plates rather than by the Young's modulus of the encapsulating membrane, in order to account for different membrane thickness, pre-inflation and nonlinear elastic deformation. We show that the maximum extension in the T-junction of capsules of different stiffness collapses onto a master curve in Ca. Thus, it provides a sensitive measure of the relative stiffness of capsules at constant flow rate, particularly for softer capsules. We also find that the T-junction can sort fixed-size capsules according to their stiffness because the position in the T-junction from which capsules are entrained into the daughter channel depends uniquely on Ca. We demonstrate that a T-junction can be used as a sorting device by enhancing this initial capsule separation through a diffuser. †

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Deformation of an elastic capsule in a microfluidic T-junction: settling shape and moduli determination

Cited by 13 publications

References 42 publications

The Physics of Detonation Chemistry: A Radical Theory in Predicting the Deflagration to Detonation Transition and Environmental Explosions

The Physics of Detonation Chemistry: A Radical Theory in Predicting the Deflagration to Detonation Transition and Environmental Explosions

Motion of an Elastic Capsule in a Trapezoidal Microchannel under Stokes Flow Conditions

Deformation and sorting of capsules in a T-junction

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