Max Planck University of Twente Center for Complex Fluid Dynamics

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Max Planck University of Twente Center for Complex Fluid Dynamics
Short name
MPUTCCFD
Country, city
Netherlands, Enschede
Publications
186
Citations
3 850
h-index
32
Top-3 journals
Journal of Fluid Mechanics
Journal of Fluid Mechanics (59 publications)
Physical Review Fluids
Physical Review Fluids (16 publications)
Physical Review Letters
Physical Review Letters (12 publications)
Top-3 organizations
Top-3 foreign organizations

Most cited in 5 years

Lohse D.
2022-01-05 citations by CoLab: 371 Abstract  
Inkjet printing is the most widespread technological application of microfluidics. It is characterized by its high drop productivity, small volumes, and extreme reproducibility. This review gives a synopsis of the fluid dynamics of inkjet printing and discusses the main challenges for present and future research. These lie both on the printhead side—namely, the detailed flow inside the printhead, entrained bubbles, the meniscus dynamics, wetting phenomena at the nozzle plate, and jet formation—and on the receiving substrate side—namely, droplet impact, merging, wetting of the substrate, droplet evaporation, and drying. In most cases the droplets are multicomponent, displaying rich physicochemical hydrodynamic phenomena. The challenges on the printhead side and on the receiving substrate side are interwoven, as optimizing the process and the materials with respect to either side alone is not enough: As the same ink (or other jetted liquid) is used and as droplet frequency and size matter on both sides, the process must be optimized as a whole.
Lohse D., Zhang X.
Nature Reviews Physics scimago Q1 wos Q1
2020-07-23 citations by CoLab: 156 Abstract  
Droplets abound in nature and technology. In general, they are multicomponent, and, when out of equilibrium, have gradients in concentration, implying flow and mass transport. Moreover, phase transitions can occur, in the form of evaporation, solidification, dissolution or nucleation of a new phase. The droplets and their surrounding liquid can be binary, ternary or contain even more components, with several in different phases. Since the early 2000s, rapid advances in experimental and numerical fluid dynamical techniques have enabled major progress in our understanding of the physicochemical hydrodynamics of such droplets, further narrowing the gap from fluid dynamics to chemical engineering and colloid and interfacial science, arriving at a quantitative understanding of multicomponent and multiphase droplet systems far from equilibrium, and aiming towards a one-to-one comparison between experiments and theory or numerics. This Perspective discusses examples of the physicochemical hydrodynamics of droplet systems far from equilibrium and the relevance of such systems for applications. Droplets in general are multicomponent and experience gradients in concentration, often leading to transport phenomena and phase transitions. This Perspective discusses recent progress on the physicochemical hydrodynamics of such droplet systems and their relevance for many important applications.
Chong K.L., Ng C.S., Hori N., Yang R., Verzicco R., Lohse D.
Physical Review Letters scimago Q1 wos Q1 Open Access
2021-01-19 citations by CoLab: 143 Abstract  
To quantify the fate of respiratory droplets under different ambient relative humidities, direct numerical simulations of a typical respiratory event are performed. We found that, because small droplets (with initial diameter of 10um) are swept by turbulent eddies in the expelled humid puff, their lifetime gets extended by a factor of more than 30 times as compared to what is suggested by the classical picture by William F. Wells, for 50% relative humidity. With increasing ambient relative humidity the extension of the lifetimes of the small droplets further increases and goes up to around 150 times for 90% relative humidity, implying more than two meters advection range of the respiratory droplets within one second. Employing Lagrangian statistics, we demonstrate that the turbulent humid respiratory puff engulfs the small droplets, leading to many orders of magnitude increase in their lifetimes, implying that they can be transported much further during the respiratory events than the large ones. Our findings provide the starting points for larger parameter studies and may be instructive for developing strategies on optimizing ventilation and indoor humidity control. Such strategies are key in mitigating the COVID-19 pandemic in the present autumn and upcoming winter.
Wang J., Pinkse P.W., Segerink L.I., Eijkel J.C.
ACS Nano scimago Q1 wos Q1
2021-05-24 citations by CoLab: 101 Abstract  
Photonic crystals (PhCs) display photonic stop bands (PSBs) and at the edges of these PSBs transport light with reduced velocity, enabling the PhCs to confine and manipulate incident light with enhanced light–matter interaction. Intense research has been devoted to leveraging the optical properties of PhCs for the development of optical sensors for bioassays, diagnosis, and environmental monitoring. These applications have furthermore benefited from the inherently large surface area of PhCs, giving rise to high analyte adsorption and the wide range of options for structural variations of the PhCs leading to enhanced light–matter interaction. Here, we focus on bottom-up assembled PhCs and review the significant advances that have been made in their use as label-free sensors. We describe their potential for point-of-care devices and in the review include their structural design, constituent materials, fabrication strategy, and sensing working principles. We thereby classify them according to five sensing principles: sensing of refractive index variations, sensing by lattice spacing variations, enhanced fluorescence spectroscopy, surface-enhanced Raman spectroscopy, and configuration transitions.
van Gelder M.K., Jong J.A., Folkertsma L., Guo Y., Blüchel C., Verhaar M.C., Odijk M., Van Nostrum C.F., Hennink W.E., Gerritsen K.G.
Biomaterials scimago Q1 wos Q1 Open Access
2020-03-01 citations by CoLab: 89 Abstract  
The availability of a wearable artificial kidney (WAK) that provides dialysis outside the hospital would be an important advancement for dialysis patients. The concept of a WAK is based on regeneration of a small volume of dialysate in a closed-loop. Removal of urea, the primary waste product of nitrogen metabolism, is the major challenge for the realization of a WAK since it is a molecule with low reactivity that is difficult to adsorb while it is the waste solute with the highest daily molar production. Currently, no efficient urea removal technology is available that allows for miniaturization of the WAK to a size and weight that is acceptable for patients to carry. Several urea removal strategies have been explored, including enzymatic hydrolysis by urease, electro-oxidation and sorbent systems. However, thus far, these methods have toxic side effects, limited removal capacity or slow removal kinetics. This review discusses different urea removal strategies for application in a wearable dialysis device, from both a chemical and a medical perspective.
Li Y., Diddens C., Segers T., Wijshoff H., Versluis M., Lohse D.
2020-07-02 citations by CoLab: 72 Abstract  
Significance Evaporating suspension droplets in general leave ring-like stains. For many applications requiring homogeneous deposition, the stains imply a major problem. This in particular holds for inkjet printing, surface patterning, self-assembly, and 3D printing technologies. Here we offer a robust method to suppress the coffee-stain effect by letting particle-laden droplets evaporate on oil-wetted surfaces. Through tuning the surface energy of the droplets by adding surfactants, we can manipulate the contact line behavior, the flow structure, and the wetting state of the thin film surrounding the droplet and accomplish a controlled particle deposition. Our findings may open perspectives for uniform coatings in the abovementioned applications, but are also relevant for other complex liquid droplet evaporation, e.g., for disease transmission or in agriculture.
Wang Q., Verzicco R., Lohse D., Shishkina O.
Physical Review Letters scimago Q1 wos Q1 Open Access
2020-08-12 citations by CoLab: 64 Abstract  
Recent findings suggest that wall-bounded turbulent flow can take different statistically stationary turbulent states, with different transport properties, even for the very same values of the control parameters. What state the system takes depends on the initial conditions. Here we analyze the multiple states in large-aspect ratio ($\Gamma$) two-dimensional turbulent Rayleigh--B\'enard flow with no-slip plates and horizontally periodic boundary conditions as model system. We determine the number $n$ of convection rolls, their mean aspect ratios $\Gamma_r = \Gamma /n$, and the corresponding transport properties of the flow (i.e., the Nusselt number $Nu$), as function of the control parameters Rayleigh ($Ra$) and Prandtl number. The effective scaling exponent $\beta$ in $Nu \sim Ra^\beta$ is found to depend on the realized state and thus $\Gamma_r$, with a larger value for the smaller $\Gamma_r$. By making use of a generalized Friedrichs inequality, we show that the elliptical instability and viscous damping determine the $\Gamma_r$-window for the realizable turbulent states. The theoretical results are in excellent agreement with our numerical finding $2/3 \le \Gamma_r \le 4/3$, where the lower threshold is approached for the larger $Ra$. Finally, we show that the theoretical approach to frame $\Gamma_r$ also works for free-slip boundary conditions.
Li S., Meer D.V., Zhang A., Prosperetti A., Lohse D.
2020-01-01 citations by CoLab: 59 Abstract  
A thorough understanding of the dynamics of meter-sized airgun-bubbles is very crucial to seabed geophysical exploration. In this study, we use the boundary integral method to investigate the highly non-spherical airgun-bubble dynamics and its corresponding pressure wave emission. Moreover, a model is proposed to also consider the process of air release from the airgun port, which is found to be the most crucial factor to estimate the initial peak of the pressure wave. The numerical simulations show good agreement with experiments, in terms of non-spherical bubble shapes and pressure waves. Thereafter, the effects of the port opening time $T\rm_{open}$, airgun firing depth, heat transfer, and gravity are numerically investigated. We find that a smaller $T\rm_{open}$ leads to a more violent air release that consequently causes stronger high-frequency pressure wave emissions; however, the low-frequency pressure waves are little affected. Additionally, the non-spherical bubble dynamics is highly dependent on the Froude number $Fr$. Starting from $Fr=2$, as $Fr$ increases, the jet contains lower kinetic energy, resulting in a stronger energy focusing of the bubble collapse itself and thus a larger pressure peak during the bubble collapse phase. For $Fr \ge 7$, the spherical bubble theory becomes an appropriate description of the airgun-bubble. The new findings of this study may provide a reference for practical operations and designing environmentally friendly airguns in the near future.
Diddens C., Li Y., Lohse D.
Journal of Fluid Mechanics scimago Q1 wos Q1
2021-03-05 citations by CoLab: 57 Abstract  
Abstract For a small sessile or pendant droplet it is generally assumed that gravity does not play any role once the Bond number is small. This is even assumed for evaporating binary sessile or pendant droplets, in which convective flows can be driven due to selective evaporation of one component and the resulting concentration and thus surface tension differences at the air–liquid interface. However, recent studies have shown that in such droplets gravity indeed can play a role and that natural convection can be the dominant driving mechanism for the flow inside evaporating binary droplets (Edwards et al., Phys. Rev. Lett., vol. 121, 2018, 184501; Li et al., Phys. Rev. Lett., vol. 122, 2019, 114501). In this study, we derive and validate a quasi-stationary model for the flow inside evaporating binary sessile and pendant droplets, which successfully allows one to predict the prevalence and the intriguing interaction of Rayleigh and/or Marangoni convection on the basis of a phase diagram for the flow field expressed in terms of the Rayleigh and Marangoni numbers.
Yang R., Chong K.L., Wang Q., Verzicco R., Shishkina O., Lohse D.
Physical Review Letters scimago Q1 wos Q1 Open Access
2020-10-09 citations by CoLab: 52 Abstract  
Many natural and industrial turbulent flows are subjected to time-dependent boundary conditions. Despite being ubiquitous, the influence of temporal modulations (with frequency $f$) on global transport properties has hardly been studied. Here, we perform numerical simulations of Rayleigh-B\'enard (RB) convection with time periodic modulation in the temperature boundary condition and report how this modulation can lead to a significant heat flux (Nusselt number $\rm{Nu}$) enhancement. Using the concept of Stokes thermal boundary layer, we can explain the onset frequency of the Nu enhancement and the optimal frequency at which Nu is maximal, and how they depend on the Rayleigh number Ra and Prandtl number $\rm{Pr}$. From this, we construct a phase diagram in the 3D parameter space ($f$, $\rm{Ra}$, $\rm{Pr}$) and identify: (i) a regime where the modulation is too fast to affect $\rm{Nu}$; (ii) a moderate modulation regime, where $\rm{Nu}$ increases with decreasing $f$ and (iii) slow modulation regime, where $\rm{Nu}$ decreases with further decreasing $f$. Our findings provide a framework to study other types of turbulent flows with time-dependent forcing.
Wakata Y., Wang F., Sun C., Lohse D.
2025-02-07 citations by CoLab: 0 Abstract  
Volatile multicomponent liquid films show rich dynamics, due to the complex interplay of gradients in temperature and in solute concentrations. Here, we study the evaporation dynamics of a tricomponent liquid film, consisting of water, ethanol, and trans-anethole oil (known as “ouzo”). With the preferential evaporation of ethanol, cellular convective structures are observed both in the thermal patterns and in the nucleated oil droplet patterns. However, the feature sizes of these two patterns can differ, indicating dual instability mechanisms dominated by either temperature or solute concentration. Using numerical simulations, we quantitatively compare the contributions of temperature and solute concentration on the surface tension. Our results reveal that the thermal Marangoni effect predominates at the initial evaporation stage, resulting in cellular patterns in thermal images, while the solutal Marangoni effect gradually becomes dominant. By regulating the transition time of this thermal-solutal-induced bistability and the nucleation time of oil microdroplets in the ternary mixture, the oil droplet patterns can be well controlled. This capability not only enhances our understanding of the evaporation dynamics but also paves the way for precise manipulation of nucleation and deposition processes at larger scales.
Diddens C., Rocha D.
2024-12-01 citations by CoLab: 4 Abstract  
We present a black-box method to numerically investigate the linear stability of arbitrary multi-physics problems. While the user just has to enter the system's residual in weak formulation, e.g. by a finite element method, all required discretized matrices are automatically assembled based on just-in-time generated and compiled C codes. Based on this method, entire phase diagrams in the parameter space can be obtained by bifurcation tracking and continuation at low computational costs. Particular focus is put on problems with moving domains, e.g. free surface problems in fluid dynamics, since a moving mesh introduces a plethora of complicated nonlinearities to the system. By symbolic differentiation before the code generation, however, these moving mesh problems are made accessible to bifurcation tracking methods. In a second step, our method is generalized to investigate symmetry-breaking instabilities of axisymmetric stationary solutions by effectively utilizing the symmetry of the base state. Each bifurcation type is validated on the basis of results reported in the literature on versatile fluid dynamics problems, for which we subsequently present novel results as well.
Yerragolam G.S., Howland C.J., Stevens R.J., Verzicco R., Shishkina O., Lohse D.
Journal of Fluid Mechanics scimago Q1 wos Q1
2024-11-28 citations by CoLab: 3 Abstract  
We provide scaling relations for the Nusselt number $Nu$ and the friction coefficient $C_{S}$ in sheared Rayleigh–Bénard convection, i.e. in Rayleigh–Bénard flow with Couette- or Poiseuille-type shear forcing, by extending the Grossmann & Lohse (J. Fluid Mech., vol. 407, 2000, pp. 27–56, Phys. Rev. Lett., vol. 86, 2001, pp. 3316–3319, Phys. Rev. E, vol. 66, 2002, 016305, Phys. Fluids, vol. 16, 2004, pp. 4462–4472) theory to sheared thermal convection. The control parameters for these systems are the Rayleigh number $Ra$ , the Prandtl number $Pr$ and the Reynolds number $Re_S$ that characterises the strength of the imposed shear. By direct numerical simulations and theoretical considerations, we show that, in turbulent Rayleigh–Bénard convection, the friction coefficients associated with the applied shear and the shear generated by the large-scale convection rolls are both well described by Prandtl's (Ergeb. Aerodyn. Vers. Gött., vol. 4, 1932, pp. 18–29) logarithmic friction law, suggesting some kind of universality between purely shear-driven flows and thermal convection. These scaling relations hold well for $10^6 \leq Ra \leq 10^8$ , $0.5 \leq Pr \leq 5.0$ , and $0 \leq Re_S \leq 10^4$ .
van Buuren D., Kant P., Meijer J.G., Diddens C., Lohse D.
Physical Review Letters scimago Q1 wos Q1 Open Access
2024-11-21 citations by CoLab: 1 Abstract  
A uniform solidification front undergoes nontrivial deformations when encountering an insoluble dispersed particle in a melt. For solid particles, the overall deformation characteristics are primarily dictated by heat transfer between the particle and the surrounding, remaining unaffected by the rate of approach of the solidification front. In this Letter we show that, conversely, when interacting with a droplet or a bubble, the deformation behavior exhibits entirely different and unexpected behavior. It arises from an interfacial dynamics which is specific to particles with free interfaces, namely, thermal Marangoni forces. Our Letter employs a combination of experiments, theory, and numerical simulations to investigate the interaction between the droplet and the freezing front and unveils its surprising behavior. In particular, we quantitatively understand the dependence of the front deformation Δ on the front propagation velocity, set by the strength of the applied thermal gradient, which, for larger front velocities (larger applied thermal gradients), can even revert from attraction (Δ<0) to repulsion (Δ>0). Published by the American Physical Society 2024
Yang R., Howland C.J., Liu H., Verzicco R., Lohse D.
2024-11-05 citations by CoLab: 0 Abstract  
Latent heat storage (LHS) has emerged as a promising solution for addressing the challenges of large-scale and long-term energy storage, offering a clean and reusable system. Being in the developmental stage, and with only limited theoretical predictions being available, there is a need to enhance the efficiency of LHS systems. In this study, we use numerical simulations to study the melting process of a phase-change material (PCM) in a rectangular domain. A significant enhancement in the melt rate of the PCM is found by a simple inclination of the domain, with a 60% increase in melt rate compared to a standard square unit without inclination through enhanced heat transfer. We establish a theoretical relation for the optimal PCM melt rate, based on the inclination angle and the domain aspect ratio, outlining the optimal conditions for the PCM melt rate, which is solely dependent on the domain geometry. We further propose a heat-transfer model that predicts the optimal aspect ratio for achieving the maximum melt rate as a function of the Rayleigh and Prandtl numbers. Published by the American Physical Society 2024
Engelen Y., Krysko D.V., Effimova I., Breckpot K., Versluis M., De Smedt S., Lajoinie G., Lentacker I.
Journal of Controlled Release scimago Q1 wos Q1
2024-11-01 citations by CoLab: 0 Abstract  
Over the past decade, ultrasound (US) has gathered significant attention and research focus in the realm of medical treatments, particularly within the domain of anti-cancer therapies. This growing interest can be attributed to its non-invasive nature, precision in delivery, availability, and safety. While the conventional objective of US-based treatments to treat breast, prostate, and liver cancer is the ablation of target tissues, the introduction of the concept of immunogenic cell death (ICD) has made clear that inducing cell death can take different non-binary pathways through the activation of the patient's anti-tumor immunity. Here, we investigate high-intensity focused ultrasound (HIFU) to induce ICD by unraveling the underlying physical phenomena and resulting biological effects associated with HIFU therapy using an automated and fully controlled experimental setup. Our in-vitro approach enables the treatment of adherent cancer cells (B16F10 and CT26), analysis for ICD hallmarks and allows to monitor and characterize in real time the US-induced cavitation activity through passive cavitation detection (PCD). We demonstrate HIFU-induced cell death, CRT exposure, HMGB1 secretion and antigen release. This approach holds great promise in advancing our understanding of the therapeutic potential of HIFU for anti-cancer strategies.
Hack M.A., van der Linden M.N., Wijshoff H., Snoeijer J.H., Segers T.
2024-11-01 citations by CoLab: 0 Abstract  
Electrostatically stabilised colloidal particles destabilise when brought into contact with cations causing the particles to aggregate in clusters. When a drop with stabilised colloidal partices is deposited on a liquid film containing cations the delicate balance between the fluid-mechanical and physicochemical properties of the system governs the spreading dynamics and formation of colloidal particle clusters. High-speed imaging and digital holographic microscopy were used to characterise the spreading process. We reveal that a spreading colloidal drop evolves into a ring-shaped pattern after it is deposited on a thin saline water film. Clustered colloidal particles aggregate into larger trapezoidally-shaped 'supraclusters'. Using a simple model we show that the trapezoidal shape of the supraclusters is determined by the transition from inertial spreading dynamics to Marangoni flow. These results may be of interest to applications such as wet-on-wet inkjet printing, where particle destabilisation and hydrodynamic flow coexist.
Yang R., Chong K.L., Liu H., Verzicco R., Lohse D.
Journal of Fluid Mechanics scimago Q1 wos Q1
2024-10-25 citations by CoLab: 0 Abstract  
Melting and solidification in periodically time-modulated thermal convection are relevant for numerous natural and engineering systems, for example, glacial melting under periodic sun radiation and latent thermal energy storage under periodically pulsating heating. It is highly relevant for the estimation of melt rate and melt efficiency management. However, even the dynamics of a solid–liquid interface shape subjected to a simple sinusoidal heating has not yet been investigated in detail. In this paper, we offer a better understanding of the modulation frequency dependence of the melting and solidification front. We numerically investigate periodic melting and solidification in turbulent convective flow with the solid above and the melted liquid below, and sinusoidal heating at the bottom plate with the mean temperature equal to the melting temperature. We investigate how the periodic heating can prevent the full solidification, and the resulting flow structures and the quasi-equilibrium interface height. We further study the dependence on the heating modulation frequency. As the frequency decreases, we found two distinct regimes, which are ‘partially solid’ and ‘fully solid’. In the fully solid regime, the liquid freezes completely, and the effect of the modulation is limited. In the partially solid regime, the solid partially melts, and a steady or unsteady solid–liquid interface forms depending on the frequency. The interface height can be derived based on the energy balance through the interface. In the partially solid regime, the interface height oscillates periodically, following the frequency of modulation. Here, we propose a perturbation approach that can predict the dependency of the oscillation amplitude on the modulation frequency.
Piumini G., Assen M.P., Lohse D., Verzicco R.
Journal of Fluid Mechanics scimago Q1 wos Q1
2024-09-20 citations by CoLab: 0 Abstract  
We use three-dimensional direct numerical simulations of homogeneous isotropic turbulence in a cubic domain to investigate the dynamics of heavy, chiral, finite-size inertial particles and their effects on the flow. Using an immersed-boundary method and a complex collision model, four-way coupled simulations have been performed, and the effects of particle-to-fluid density ratio, turbulence strength and particle volume fraction have been analysed. We find that freely falling particles on the one hand add energy to the turbulent flow but, on the other hand, they also enhance the flow dissipation: depending on the combination of flow parameters, the former or the latter mechanism prevails, thus yielding enhanced or weakened turbulence. Furthermore, particle chirality entails a preferential angular velocity which induces a net vorticity in the fluid phase. As turbulence strengthens, the energy introduced by the falling particles becomes less relevant and stronger velocity fluctuations alter the solid phase dynamics, making the effect of chirality irrelevant for the large-scale features of the flow. Moreover, comparing the time history of collision events for chiral particles and spheres (at the same volume fraction) suggests that the former tend to entangle, in contrast to the latter which rebound impulsively.
Harte N.C., Obrist D., Caversaccio M., Lajoinie G.P., Wimmer W.
2024-09-01 citations by CoLab: 3 Abstract  
The cochlea, situated within the inner ear, is a spiral-shaped, liquid-filled organ responsible for hearing. The physiological significance of its shape remains uncertain. Previous research has scarcely addressed the occurrence of transverse flow within the cochlea, particularly in relation to its unique shape. This study aims to investigate the impact of the geometric features of the cochlea on fluid dynamics by characterizing transverse flow induced by harmonically oscillating axial flow in square ducts with curvature and torsion resembling human cochlear anatomy. We examined four geometries to investigate curvature and torsion effects on axial and transverse flow components. Twelve frequencies from 0.125 Hz to 256 Hz were studied, covering infrasound and low-frequency hearing, with mean inlet velocity amplitudes representing levels expected for normal conversation or louder situations. Our simulations show that torsion contributes significantly to transverse flow in unsteady conditions, and that its contribution increases with increasing oscillation frequency. Curvature alone has a small effect on transverse flow strength, which decreases rapidly with increasing frequency. Strikingly, the combined effect of curvature and torsion on transverse flow is greater than expected from a simple superposition of the two effects, especially when the relative contribution of curvature alone becomes negligible. These findings may be relevant to understanding physiological processes in the cochlea, including metabolite transport and wall shear stress. Further studies are needed to investigate possible implications for cochlear mechanics.
Nawijn C.L., Segers T., Lajoinie G., Berg S., Snipstad S., Davies C.D., Versluis M.
2024-08-01 citations by CoLab: 0 Abstract  
Ultrasound-triggered bubble-mediated local drug delivery has shown potential to increase therapeutic efficacy and reduce systemic side effects, by loading drugs into the microbubble shell and triggering delivery of the payload on demand using ultrasound. Understanding the behavior of the microbubbles in response to ultrasound is crucial for efficient and controlled release.
Zhu X., Fu Y., De Paoli M.
Journal of Fluid Mechanics scimago Q1 wos Q1
2024-07-25 citations by CoLab: 6 Abstract  
We present a theory to describe the Nusselt number, $\operatorname {\mathit {Nu}}$ , corresponding to the heat or mass flux, as a function of the Rayleigh–Darcy number, $\operatorname {\mathit {Ra}}$ , the ratio of buoyant driving force over diffusive dissipation, in convective porous media flows. First, we derive exact relationships within the system for the kinetic energy and the thermal dissipation rate. Second, by segregating the thermal dissipation rate into contributions from the boundary layer and the bulk, which is inspired by the ideas of the Grossmann and Lohse theory (J. Fluid Mech., vol. 407, 2000; Phys. Rev. Lett., vol. 86, 2001), we derive the scaling relation for $\operatorname {\mathit {Nu}}$ as a function of $\operatorname {\mathit {Ra}}$ and provide a robust theoretical explanation for the empirical relations proposed in previous studies. Specifically, by incorporating the length scale of the flow structure into the theory, we demonstrate why heat or mass transport differs between two-dimensional and three-dimensional porous media convection. Our model is in excellent agreement with the data obtained from numerical simulations, affirming its validity and predictive capabilities.
Rudravaram S., Shukla R.P., Maheshwaram S.
Physica Scripta scimago Q2 wos Q2
2024-07-18 citations by CoLab: 0 Abstract  
Abstract In this work we report a vertically stacked nanosheet Field Effect Transistor (NSFET) in double gate configuration using transition metal dichalcogenide (TMD) based molybdenum disulphide (MoS2) as the conducting channel. The performance of the NSFET is analysed for number of channels, different channel thickness, different source/drain contacts. The performance of the device at different temperatures (T) also analysed. The proposed NSFET with three vertically stacked channels, exhibits a ON current (ION) of 30.6 μA μm−1, Subthreshold swing (SS) of 69 mV/dec and ON to OFF current ratio of more than 108 at Vds = 1V. Further the ION can be improved with multi-layer channel thickness. The performance of the vertically stacked MoS2 NSFET in junction less (JL) and inversion mode (IM) is compared, it is concluded from the simulations that JL vertically stacked MoS2 NSFET more immune to short channel effects such as threshold voltage (Vth) roll-off and drain induced barrier lowering (DIBL).

Since 2017

Total publications
186
Total citations
3850
Citations per publication
20.7
Average publications per year
23.25
Average authors per publication
5.33
h-index
32
Metrics description

Top-30

Fields of science

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Condensed Matter Physics, 70, 37.63%
Mechanical Engineering, 68, 36.56%
Mechanics of Materials, 61, 32.8%
General Physics and Astronomy, 37, 19.89%
Applied Mathematics, 26, 13.98%
Fluid Flow and Transfer Processes, 26, 13.98%
General Chemistry, 20, 10.75%
General Materials Science, 18, 9.68%
Modeling and Simulation, 17, 9.14%
Computational Mechanics, 15, 8.06%
Biochemistry, 11, 5.91%
Analytical Chemistry, 9, 4.84%
Bioengineering, 9, 4.84%
Multidisciplinary, 8, 4.3%
Biomedical Engineering, 8, 4.3%
Electrical and Electronic Engineering, 7, 3.76%
Instrumentation, 7, 3.76%
General Engineering, 7, 3.76%
Atomic and Molecular Physics, and Optics, 6, 3.23%
Electrochemistry, 5, 2.69%
Biotechnology, 5, 2.69%
Biomaterials, 5, 2.69%
General Biochemistry, Genetics and Molecular Biology, 4, 2.15%
Spectroscopy, 4, 2.15%
General Medicine, 4, 2.15%
Physics and Astronomy (miscellaneous), 4, 2.15%
General Earth and Planetary Sciences, 4, 2.15%
Computer Science Applications, 3, 1.61%
Clinical Biochemistry, 3, 1.61%
Colloid and Surface Chemistry, 3, 1.61%
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Germany, 105, 56.45%
China, 46, 24.73%
Italy, 43, 23.12%
USA, 25, 13.44%
United Kingdom, 14, 7.53%
France, 8, 4.3%
Australia, 7, 3.76%
Canada, 7, 3.76%
Belgium, 6, 3.23%
India, 4, 2.15%
Spain, 4, 2.15%
Switzerland, 4, 2.15%
Austria, 3, 1.61%
Vietnam, 2, 1.08%
Luxembourg, 2, 1.08%
Republic of Korea, 2, 1.08%
Singapore, 2, 1.08%
Portugal, 1, 0.54%
Argentina, 1, 0.54%
Brazil, 1, 0.54%
Denmark, 1, 0.54%
Israel, 1, 0.54%
Lithuania, 1, 0.54%
Norway, 1, 0.54%
Czech Republic, 1, 0.54%
Japan, 1, 0.54%
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  • We do not take into account publications without a DOI.
  • Statistics recalculated daily.
  • Publications published earlier than 2017 are ignored in the statistics.
  • The horizontal charts show the 30 top positions.
  • Journals quartiles values are relevant at the moment.