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Fulltext Heat transfer analysis of MHD thin film flow of an unsteady second grade fluid past a vertical oscillating belt

Gul T, Islam S, Shah RA, Khan I, Khalid A, Shafie S

PLoS One, 2014;9(11):e103843.
PMID: 25383797 DOI: 10.1371/journal.pone.0103843

This article aims to study the thin film layer flowing on a vertical oscillating belt. The flow is considered to satisfy the constitutive equation of unsteady second grade fluid. The governing equation for velocity and temperature fields with subjected initial and boundary conditions are solved by two analytical techniques namely Adomian Decomposition Method (ADM) and Optimal Homotopy Asymptotic Method (OHAM). The comparisons of ADM and OHAM solutions for velocity and temperature fields are shown numerically and graphically for both the lift and drainage problems. It is found that both these solutions are identical. In order to understand the physical behavior of the embedded parameters such as Stock number, frequency parameter, magnetic parameter, Brinkman number and Prandtl number, the analytical results are plotted graphically and discussed.

Matched MeSH terms: Hydrodynamics*
Fulltext Thin film flow in MHD third grade fluid on a vertical belt with temperature dependent viscosity

Gul T, Islam S, Shah RA, Khan I, Shafie S

PLoS One, 2014;9(6):e97552.
PMID: 24949988 DOI: 10.1371/journal.pone.0097552

In this work, we have carried out the influence of temperature dependent viscosity on thin film flow of a magnetohydrodynamic (MHD) third grade fluid past a vertical belt. The governing coupled non-linear differential equations with appropriate boundary conditions are solved analytically by using Adomian Decomposition Method (ADM). In order to make comparison, the governing problem has also been solved by using Optimal Homotopy Asymptotic Method (OHAM). The physical characteristics of the problem have been well discussed in graphs for several parameter of interest.

Matched MeSH terms: Hydrodynamics*
Fulltext Unsteady magnetohydrodynamic free convection flow of a second grade fluid in a porous medium with ramped wall temperature

Samiulhaq, Ahmad S, Vieru D, Khan I, Shafie S

PLoS One, 2014;9(5):e88766.
PMID: 24785147 DOI: 10.1371/journal.pone.0088766

Magnetic field influence on unsteady free convection flow of a second grade fluid near an infinite vertical flat plate with ramped wall temperature embedded in a porous medium is studied. It has been observed that magnitude of velocity as well as skin friction in case of ramped temperature is quite less than the isothermal temperature. Some special cases namely: (i) second grade fluid in the absence of magnetic field and porous medium and (ii) Newtonian fluid in the presence of magnetic field and porous medium, performing the same motion are obtained. Finally, the influence of various parameters is graphically shown.

Matched MeSH terms: Hydrodynamics*
Fulltext Effects of wall shear stress on unsteady MHD conjugate flow in a porous medium with ramped wall temperature

Khan A, Khan I, Ali F, Ulhaq S, Shafie S

PLoS One, 2014;9(3):e90280.
PMID: 24621775 DOI: 10.1371/journal.pone.0090280

This study investigates the effects of an arbitrary wall shear stress on unsteady magnetohydrodynamic (MHD) flow of a Newtonian fluid with conjugate effects of heat and mass transfer. The fluid is considered in a porous medium over a vertical plate with ramped temperature. The influence of thermal radiation in the energy equations is also considered. The coupled partial differential equations governing the flow are solved by using the Laplace transform technique. Exact solutions for velocity and temperature in case of both ramped and constant wall temperature as well as for concentration are obtained. It is found that velocity solutions are more general and can produce a huge number of exact solutions correlative to various fluid motions. Graphical results are provided for various embedded flow parameters and discussed in details.

Matched MeSH terms: Hydrodynamics*
Fulltext Conjugate effects of heat and mass transfer on MHD free convection flow over an inclined plate embedded in a porous medium

Ali F, Khan I, Samiulhaq, Shafie S

PLoS One, 2013;8(6):e65223.
PMID: 23840321 DOI: 10.1371/journal.pone.0065223

The aim of this study is to present an exact analysis of combined effects of radiation and chemical reaction on the magnetohydrodynamic (MHD) free convection flow of an electrically conducting incompressible viscous fluid over an inclined plate embedded in a porous medium. The impulsively started plate with variable temperature and mass diffusion is considered. The dimensionless momentum equation coupled with the energy and mass diffusion equations are analytically solved using the Laplace transform method. Expressions for velocity, temperature and concentration fields are obtained. They satisfy all imposed initial and boundary conditions and can be reduced, as special cases, to some known solutions from the literature. Expressions for skin friction, Nusselt number and Sherwood number are also obtained. Finally, the effects of pertinent parameters on velocity, temperature and concentration profiles are graphically displayed whereas the variations in skin friction, Nusselt number and Sherwood number are shown through tables.

Matched MeSH terms: Hydrodynamics
Fulltext Stokes' second problem for magnetohydrodynamics flow in a Burgers' fluid: the cases γ = λ²/4 and γ>λ²/4

Khan I, Ali F, Shafie S

PLoS One, 2013;8(5):e61531.
PMID: 23667442 DOI: 10.1371/journal.pone.0061531

The present work is concerned with exact solutions of Stokes second problem for magnetohydrodynamics (MHD) flow of a Burgers' fluid. The fluid over a flat plate is assumed to be electrically conducting in the presence of a uniform magnetic field applied in outward transverse direction to the flow. The equations governing the flow are modeled and then solved using the Laplace transform technique. The expressions of velocity field and tangential stress are developed when the relaxation time satisfies the condition γ = λ²/4 or γ> λ²/4. The obtained closed form solutions are presented in the form of simple or multiple integrals in terms of Bessel functions and terms with only Bessel functions. The numerical integration is performed and the graphical results are displayed for the involved flow parameters. It is found that the velocity decreases whereas the shear stress increases when the Hartmann number is increased. The solutions corresponding to the Stokes' first problem for hydrodynamic Burgers' fluids are obtained as limiting cases of the present solutions. Similar solutions for Stokes' second problem of hydrodynamic Burgers' fluids and those for Newtonian and Oldroyd-B fluids can also be obtained as limiting cases of these solutions.

Matched MeSH terms: Hydrodynamics*
Fulltext Unsteady MHD Thin Film Flow of an Oldroyd-B Fluid over an Oscillating Inclined Belt

Gul T, Islam S, Shah RA, Khalid A, Khan I, Shafie S

PLoS One, 2015;10(7):e0126698.
PMID: 26147287 DOI: 10.1371/journal.pone.0126698

This paper studies the unsteady magnetohydrodynamics (MHD) thin film flow of an incompressible Oldroyd-B fluid over an oscillating inclined belt making a certain angle with the horizontal. The problem is modeled in terms of non-linear partial differential equations with some physical initial and boundary conditions. This problem is solved for the exact analytic solutions using two efficient techniques namely the Optimal Homotopy Asymptotic Method (OHAM) and Homotopy Perturbation Method (HPM). Both of these solutions are presented graphically and compared. This comparison is also shown in tabular form. An excellent agreement is observed. The effects of various physical parameters on velocity have also been studied graphically.

Matched MeSH terms: Hydrodynamics*
Transient electro-magneto-hydrodynamic two-phase blood flow and thermal transport through a capillary vessel

Mirza IA, Abdulhameed M, Vieru D, Shafie S

Comput Methods Programs Biomed, 2016 Dec;137:149-166.
PMID: 28110721 DOI: 10.1016/j.cmpb.2016.09.014

Therapies with magnetic/electromagnetic field are employed to relieve pains or, to accelerate flow of blood-particles, particularly during the surgery. In this paper, a theoretical study of the blood flow along with particles suspension through capillary was made by the electro-magneto-hydrodynamic approach. Analytical solutions to the non-dimensional blood velocity and non-dimensional particles velocity are obtained by means of the Laplace transform with respect to the time variable and the finite Hankel transform with respect to the radial coordinate. The study of thermally transfer characteristics is based on the energy equation for two-phase thermal transport of blood and particles suspension with viscous dissipation, the volumetric heat generation due to Joule heating effect and electromagnetic couple effect. The solution of the nonlinear heat transfer problem is derived by using the velocity field and the integral transform method. The influence of dimensionless system parameters like the electrokinetic width, the Hartman number, Prandtl number, the coefficient of heat generation due to Joule heating and Eckert number on the velocity and temperature fields was studied using the Mathcad software. Results are presented by graphical illustrations.

Matched MeSH terms: Hydrodynamics*
Electrokinetic supercharging in nonaqueous capillary electrophoresis for online preconcentration and determination of tamoxifen and its metabolites in human plasma

Thang LY, Breadmore MC, See HH

J Chromatogr A, 2016 Jul 27.
PMID: 27485148 DOI: 10.1016/j.chroma.2016.07.067

An online preconcentration method, namely electrokinetic supercharging (EKS), was evaluated for the determination of tamoxifen and its metabolites in human plasma in nonaqueous capillary electrophoresis with ultraviolet detection (NACE-UV). This method was comprehensively optimized in terms of the leading electrolyte (LE) and terminating electrolyte (TE) injection lengths, as well as electrokinetic sample injection time. The optimized EKS conditions employed were as follows: hydrodynamic injection (HI) of 10mM potassium chloride as LE at 150mbar for 36s (4% of total capillary volume). The sample was injected at 10kV for 300s, followed by HI of 10mM pimozide as TE at 150mbar for 36s (4% of total capillary volume). Separation was performed in 7.5mM deoxycholic acid sodium salt, 15mM acetic acid and 1mM 18-crown-6 in 100% methanol at +25kV with UV detection at 205nm. Under optimized conditions, the sensitivity was enhanced between 160- and 600-fold when compared with our previously developed method based on HI at 150mbar for 12s. The detection limit of the method for tamoxifen and its metabolites were 0.05-0.25ng/mL, with RSDs between 2.1% and 3.5%. Recoveries in spiked human plasma were 95.6%-99.7%. A comparison was also made between the proposed EKS approach and the standard field-amplified sample injection (FASI) technique. EKS proved to be 3-5 times more sensitive than the FASI. The new EKS method was applied to the analysis of tamoxifen and its metabolites in plasma samples from breast cancer patients after liquid-liquid extraction.

Matched MeSH terms: Hydrodynamics
Effect of porous media of the stenosed artery wall to the coronary physiological diagnostic parameter: a computational fluid dynamic analysis

Govindaraju K, Kamangar S, Badruddin IA, Viswanathan GN, Badarudin A, Salman Ahmed NJ

Atherosclerosis, 2014 Apr;233(2):630-635.
PMID: 24549189 DOI: 10.1016/j.atherosclerosis.2014.01.043

Functional assessment of a coronary artery stenosis severity is generally assessed by fractional flow reserve (FFR), which is calculated from pressure measurements across the stenosis. The purpose of this study is to investigate the effect of porous media of the stenosed arterial wall on this diagnostic parameter. To understand the role of porous media on the diagnostic parameter FFR, a 3D computational simulations of the blood flow in rigid and porous stenotic artery wall models are carried out under steady state and transient conditions for three different percentage area stenoses (AS) corresponding to 70% (moderate), 80% (intermediate), and 90% (severe). Blood was modeled as a non Newtonian fluid. The variations of pressure drop across the stenosis and diagnostic parameter were studied in both models. The FFR decreased in proportion to the increase in the severity of the stenosis. The relationship between the percentage AS and the FFR was non linear and inversely related in both the models. The cut-off value of 0.75 for FFR was observed at 81.89% AS for the rigid artery model whereas 83.61% AS for the porous artery wall model. This study demonstrates that the porous media consideration on the stenotic arterial wall plays a substantial role in defining the cut-off value of FFR. We conclude that the effect of porous media on FFR, could lead to misinterpretation of the functional severity of the stenosis in the region of 81.89 %-83.61% AS.

Matched MeSH terms: Hydrodynamics
Fulltext Numerical investigation of heat transfer enhancement in a rectangular heated pipe for turbulent nanofluid

Yarmand H, Gharehkhani S, Kazi SN, Sadeghinezhad E, Safaei MR

ScientificWorldJournal, 2014;2014:369593.
PMID: 25254236 DOI: 10.1155/2014/369593

Thermal characteristics of turbulent nanofluid flow in a rectangular pipe have been investigated numerically. The continuity, momentum, and energy equations were solved by means of a finite volume method (FVM). The symmetrical rectangular channel is heated at the top and bottom at a constant heat flux while the sides walls are insulated. Four different types of nanoparticles Al2O3, ZnO, CuO, and SiO2 at different volume fractions of nanofluids in the range of 1% to 5% are considered in the present investigation. In this paper, effect of different Reynolds numbers in the range of 5000 < Re < 25000 on heat transfer characteristics of nanofluids flowing through the channel is investigated. The numerical results indicate that SiO2-water has the highest Nusselt number compared to other nanofluids while it has the lowest heat transfer coefficient due to low thermal conductivity. The Nusselt number increases with the increase of the Reynolds number and the volume fraction of nanoparticles. The results of simulation show a good agreement with the existing experimental correlations.

Matched MeSH terms: Hydrodynamics
Fulltext Numerical study of tides in the Malacca Strait with a 3-D model

Haditiar Y, Putri MR, Ismail N, Muchlisin ZA, Ikhwan M, Rizal S

Heliyon, 2020 Sep;6(9):e04828.
PMID: 32939416 DOI: 10.1016/j.heliyon.2020.e04828

Malacca Strait (MS) has an important role and potential for many countries. It is a major transportation route for oil and commodities across continents. In addition, various activities such as shipping, fishing, aquaculture, oil drilling, and energy are also carried out in MS. Tides strongly affect the MS environment so that it becomes a major parameter in MS management. This paper is the first study, which presents MS tidal hydrodynamics based on a baroclinic and nonhydrostatic approach. Tidal hydrodynamics in MS and the surrounding waters were assessed using tidal forces, temperature, salinity, and density. This study analyzes the amplitude, phase, current ellipses, and semi-major axis of the tides. These variables are obtained from the simulation results of the three-dimensional numerical models of M2 tides and combined tides (M2, S2, N2, K1, and O1) with nonhydrostatic models. Then the results obtained are verified by observation data. Amplitude and phase of the tidal wave in MS originate from two directions, namely the northern part of MS (Andaman Sea) and the South China Sea (SCS). Tides from the north of MS propagate into the MS, while tides from the SCS travel to Singapore Waters (SW) and the south of MS. This causes a complex residual flow in SW and shoaling in the middle of MS. Shoaling in the middle of MS is characterized by a large amplitude and semi-major, as in B. Siapiapi. The results of this analysis show that tidal waves are dominated by semidiurnal types rather than diurnal types. The M2 current ellipse has dominantly anticlockwise rotation along the west of the MS, while along the east of MS, it has generally a clockwise rotation.

Matched MeSH terms: Hydrodynamics
Fulltext Quantitative Structural Analysis of Polystyrene Nanoparticles Using Synchrotron X-Ray Scattering and Dynamic Light Scattering

Wong JC, Xiang L, Ngoi KH, Chia CH, Jin KS, Ree M

Polymers (Basel), 2020 Feb 19;12(2).
PMID: 32093008 DOI: 10.3390/polym12020477

A series of polystyrene nanoparticles (PS-1, PS-2, PS-3, and PS-4) in aqueous solutions were investigated in terms of morphological structure, size, and size distribution. Synchrotron small-angle X-ray scattering analysis (SAXS) was carried out, providing morphology details, size and size distribution on the particles. PS-1, PS-2, and PS-3 were confirmed to behave two-phase (core and shell) spherical shapes, whereas PS-4 exhibited a single-phase spherical shape. They all revealed very narrow unimodal size distributions. The structural parameter details including radial density profile were determined. In addition, the presence of surfactant molecules and their assemblies were detected for all particle solutions, which could originate from their surfactant-assisted emulsion polymerizations. In addition, dynamic light scattering (DLS) analysis was performed, finding only meaningful hydrodynamic size and intensity-weighted mean size information on the individual PS solutions because of the particles' spherical nature. In contrast, the size distributions were extracted unrealistically too broad, and the volume- and number-weighted mean sizes were too small, therefore inappropriate to describe the particle systems. Furthermore, the DLS analysis could not detect completely the surfactant and their assemblies present in the particle solutions. Overall, the quantitative SAXS analysis confirmed that the individual PS particle systems were successfully prepared with spherical shape in a very narrow unimodal size distribution.

Matched MeSH terms: Hydrodynamics
A review of fluid-structure interaction simulation for patients with sleep related breathing disorders with obstructive sleep

Faizal WM, Ghazali NNN, Badruddin IA, Zainon MZ, Yazid AA, Ali MAB, et al.

Comput Methods Programs Biomed, 2019 Oct;180:105036.
PMID: 31430594 DOI: 10.1016/j.cmpb.2019.105036

Obstructive sleep apnea is one of the most common breathing disorders. Undiagnosed sleep apnea is a hidden health crisis to the patient and it could raise the risk of heart diseases, high blood pressure, depression and diabetes. The throat muscle (i.e., tongue and soft palate) relax narrows the airway and causes the blockage of the airway in breathing. To understand this phenomenon computational fluid dynamics method has emerged as a handy tool to conduct the modeling and analysis of airflow characteristics. The comprehensive fluid-structure interaction method provides the realistic visualization of the airflow and interaction with the throat muscle. Thus, this paper reviews the scientific work related to the fluid-structure interaction (FSI) for the evaluation of obstructive sleep apnea, using computational techniques. In total 102 articles were analyzed, each article was evaluated based on the elements related with fluid-structure interaction of sleep apnea via computational techniques. In this review, the significance of FSI for the evaluation of obstructive sleep apnea has been critically examined. Then the flow properties, boundary conditions and validation of the model are given due consideration to present a broad perspective of CFD being applied to study sleep apnea. Finally, the challenges of FSI simulation methods are also highlighted in this article.

Matched MeSH terms: Hydrodynamics*
Fulltext Computational fluid dynamics modelling of human upper airway: A review

Faizal WM, Ghazali NNN, Khor CY, Badruddin IA, Zainon MZ, Yazid AA, et al.

Comput Methods Programs Biomed, 2020 Nov;196:105627.
PMID: 32629222 DOI: 10.1016/j.cmpb.2020.105627

BACKGROUND AND OBJECTIVE: Human upper airway (HUA) has been widely investigated by many researchers covering various aspects, such as the effects of geometrical parameters on the pressure, velocity and airflow characteristics. Clinically significant obstruction can develop anywhere throughout the upper airway, leading to asphyxia and death; this is where recognition and treatment are essential and lifesaving. The availability of advanced computer, either hardware or software, and rapid development in numerical method have encouraged researchers to simulate the airflow characteristics and properties of HUA by using various patient conditions at different ranges of geometry and operating conditions. Computational fluid dynamics (CFD) has emerged as an efficient alternative tool to understand the airflow of HUA and in preparing patients to undergo surgery. The main objective of this article is to review the literature that deals with the CFD approach and modeling in analyzing HUA.
METHODS: This review article discusses the experimental and computational methods in the study of HUA. The discussion includes computational fluid dynamics approach and steps involved in the modeling used to investigate the flow characteristics of HUA. From inception to May 2020, databases of PubMed, Embase, Scopus, the Cochrane Library, BioMed Central, and Web of Science have been utilized to conduct a thorough investigation of the literature. There had been no language restrictions in publication and study design of the database searches. A total of 117 articles relevant to the topic under investigation were thoroughly and critically reviewed to give a clear information about the subject. The article summarizes the review in the form of method of studying the HUA, CFD approach in HUA, and the application of CFD for predicting HUA obstacle, including the type of CFD commercial software are used in this research area.
RESULTS: This review found that the human upper airway was well studied through the application of computational fluid dynamics, which had considerably enhanced the understanding of flow in HUA. In addition, it assisted in making strategic and reasonable decision regarding the adoption of treatment methods in clinical settings. The literature suggests that most studies were related to HUA simulation that considerably focused on the aspects of fluid dynamics. However, there is a literature gap in obtaining information on the effects of fluid-structure interaction (FSI). The application of FSI in HUA is still limited in the literature; as such, this could be a potential area for future researchers. Furthermore, majority of researchers present the findings of their work through the mechanism of airflow, such as that of velocity, pressure, and shear stress. This includes the use of Navier-Stokes equation via CFD to help visualize the actual mechanism of the airflow. The above-mentioned technique expresses the turbulent kinetic energy (TKE) in its result to demonstrate the real mechanism of the airflow. Apart from that, key result such as wall shear stress (WSS) can be revealed via turbulent kinetic energy (TKE) and turbulent energy dissipation (TED), where it can be suggestive of wall injury and collapsibility tissue to the HUA.

Matched MeSH terms: Hydrodynamics*
Water balance: case study of a constructed wetland as part of the bio-ecological drainage system (BIOECODS)

Ayub KR, Zakaria NA, Abdullah R, Ramli R

Water Sci Technol, 2010;62(8):1931-6.
PMID: 20962410 DOI: 10.2166/wst.2010.473

The Bio-ecological Drainage System, or BIOECODS, is an urban drainage system located at the Engineering Campus, Universiti Sains Malaysia. It consists of a constructed wetland as a part of the urban drainage system to carry storm water in a closed system. In this closed system, the constructed wetland was designed particularly for further treatment of storm water. For the purpose of studying the water balance of the constructed wetland, data collection was carried out for two years (2007 and 2009). The results show that the constructed wetland has a consistent volume of water storage compared to the outflow for both years with correlation coefficients (R(2)) of 0.99 in 2007 and 0.86 in 2009.

Matched MeSH terms: Hydrodynamics
Fulltext The magnetohydrodynamic stagnation point flow of a nanofluid over a stretching/shrinking sheet with suction

Mansur S, Ishak A, Pop I

PLoS One, 2015;10(3):e0117733.
PMID: 25760733 DOI: 10.1371/journal.pone.0117733

The magnetohydrodynamic (MHD) stagnation point flow of a nanofluid over a permeable stretching/shrinking sheet is studied. Numerical results are obtained using boundary value problem solver bvp4c in MATLAB for several values of parameters. The numerical results show that dual solutions exist for the shrinking case, while for the stretching case, the solution is unique. A stability analysis is performed to determine the stability of the dual solutions. For the stable solution, the skin friction is higher in the presence of magnetic field and increases when the suction effect is increased. It is also found that increasing the Brownian motion parameter and the thermophoresis parameter reduces the heat transfer rate at the surface.

Matched MeSH terms: Hydrodynamics*
Fulltext Mixed convection boundary layer flow over a moving vertical flat plate in an external fluid flow with viscous dissipation effect

Bachok N, Ishak A, Pop I

PLoS One, 2013;8(4):e60766.
PMID: 23577156 DOI: 10.1371/journal.pone.0060766

The steady boundary layer flow of a viscous and incompressible fluid over a moving vertical flat plate in an external moving fluid with viscous dissipation is theoretically investigated. Using appropriate similarity variables, the governing system of partial differential equations is transformed into a system of ordinary (similarity) differential equations, which is then solved numerically using a Maple software. Results for the skin friction or shear stress coefficient, local Nusselt number, velocity and temperature profiles are presented for different values of the governing parameters. It is found that the set of the similarity equations has unique solutions, dual solutions or no solutions, depending on the values of the mixed convection parameter, the velocity ratio parameter and the Eckert number. The Eckert number significantly affects the surface shear stress as well as the heat transfer rate at the surface.

Matched MeSH terms: Hydrodynamics*
Note on dual solutions for the mixed convection boundary layer flow close to the lower stagnation point of a horizontal circular cylinder: case of constant surface heat flux

Ro?ca AV, Rosca NC, Pop I

Sains Malaysiana, 2014;43:1239-1247.

The paper reconsiders the problem of the mixed convection boundary layer flow near the lower stagnation point of a horizontal circular cylinder with a second order slip velocity model and a constant surface heat flux studied recently by RoKa et al. (2013). The ordinary (similarity) differential equations are solved numerically using the function bvp4c from Matlab for different values of the governing parameters. It is found that the similarity equations have two branches, upper and lower branch solutions, in a certain range of the mixed convection parameters. A stability analysis has been performed to show that the upper branch solutions are stable and physically realizable, while the lower branch solutions are not stable and therefore, not physically possible. This stability analysis is different by that presented by RoKa et al. (2013), who have presented a time-dependent analysis to determine the stability of the solution branches.

Matched MeSH terms: Hydrodynamics
A fluid mechanical explanation of the spontaneous reattachment of a previously detached Descemet membrane

Ismail Z, Fitt AD, Please CP

Math Med Biol, 2013 Dec;30(4):339-55.
PMID: 23054933 DOI: 10.1093/imammb/dqs028

Descemet membrane detachment (DMD) is a rare but potentially serious surgical complication that arises most often during cataract surgery. A recent study (Couch, S. M. & Baratz, K. H. (2009) Cornea, 28, 1160-1163) cited the case of a patient with DMDs in both eyes, noting that though one detachment was surgically repaired, the other spontaneously reattached and needed no further treatment. A fluid mechanical model of buoyancy-driven aqueous humour flow in the anterior chamber around a DMD is developed to explain this phenomenon. The analytical model is based on the lubrication theory limit of the Navier-Stokes equations. The flow is determined for a fixed geometry and the possible motion of the DMD is then analysed. Numerical calculations are also carried out (using COMSOL© Multiphysics) to confirm the lubrication theory results. The analytical and numerical results both show that, under the correct conditions, either spontaneous reattachment or worsening of the tear may occur. We conclude that it is possible that clinical outcomes for DMDs may be controlled by adjusting the temperature difference across the eye and/or the orientation of the patient.

Matched MeSH terms: Hydrodynamics

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