Technical Papers and Presentations

Here you will find presentations given at COMSOL Conferences around the globe. The presentations explore the innovative research and products designed by your peers using COMSOL Multiphysics. Research topics span a wide array of industries and application areas, including the electrical, mechanical, fluid, and chemical disciplines. Use the Quick Search to find presentations pertaining to your application area.

Numerical Validation of the Efficiency of Dual-Frequency Radiofrequency Ablation

A. Candeo[1] and F. Dughiero[1]
[1]Department Electrical Engineering, University of Padova, Padova, Italy

Radiofrequency Ablation (RFA) represents a valid alternative for treating liver metastases in medically complicated patients. Conventional devices currently operate at 500 kHz, due to good conducting properties of tissues. However, the use of lower frequencies (i.e. 20 kHz) has been recently reported to enhance the treatment effectiveness, due to a more pronounced difference in electrical ...

Mathematical Modeling of Zig-Zag Traveling-Wave Electro-Osmotic Micropumps

J. Hrdlicka[1], P. Cervenka[1], M. Pribyl[1], and D. Snita[1]
[1]Department of Chemical Engineering, Institute of Chemical Technology Prague, Prague, Czech Republic

In this paper we present results of the mathematical modeling of AC electroosmotic micropumps. Unlike others we use the full dynamic description, instead of the linearized model. Skewed hybrid discretization meshes are employed in order to accurately capture the main features of the studied system. Also, we introduce zig-zag electrode arrangements for traveling-wave electroosmotic micropumps. The ...

Image-Based Simulation of Electrical Impedance Techniques Applied on the Human Thorax for Cardio-Pulmonary Applications

F.K. Hermans[1], R.M. Heethaar[1], R.T. Cotton[2], and A. Harkara[2]

[1]VU University Medical Center, Amsterdam, The Netherlands
[2]Simpleware Ltd., Exeter, United Kingdom

For medical diagnostic purposes there is an increasing need for non- (or minimal) invasive techniques to measure all kinds of parameters that can provide insight in the functioning of cells, organs or organ systems. Currently, Impedance Cardiography (ICG) is used for measurements of the heart and Electric Impedance Tomography (EIT) is used for investigating lung tissue condition. This paper ...

3-D Finite Element Modeling of Brain Edema: Initial Studies on Intracranial Pressure Using COMSOL Multiphysics®

X.G. Li[1], H. von Holst[1][2], J. Ho[1], and S. Kleiven[1]

[1]Division of Neuronic Engineering, KTH, Stockholm, Sweden
[2]Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden

Brain edema is one of the most common consequences of serious traumatic brain injuries which is usually accompanied with increased Intracranial Pressure (ICP) due to water content increment. A three dimensional finite element model of brain edema is used to study intracranial pressure in this paper. Three different boundary conditions at the end of Cerebral Spinal Fluid (CSF) were used to ...

Numerical Simulations Demonstrate Safe Vitrification and Warming of Embryos Using the Rapid-i™ Device

B.O.J. Johansson[1][2], Y.A. Tarakanov[1], H.J. Lehmann[2], and S.P. Apell[1]

[1]Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden
[2]Vitrolife Sweden AB, Västra Frölunda, Sweden

During cryopreservation of human embryos, ice crystal formation in the embryos or in surrounding media may cause cryodamage to them and can be lethal. A strategy to avoid this is the vitrification procedure when the embryo and the surrounding medium undergo the transition to glassy state rather than a crystalline one during cooling. Similarly, recrystallization in the embryo or the medium must be ...

Modeling of Usage of Air Injection Well in a Geothermal System

X. Ma[1] and J. Grabe[1]

[1]Institude for Geotechnics and Construction Management, Hamburg University of Technology, Hamburg, Germany

Natural groundwater flow can increase the efficiency of geothermal system. But groundwater flow is not available everywhere. A patented new idea is to use air injection well to create artificial flow in sandy or gritty soils. The governing equations of fluid flow and heat transfer problem were solved with the COMSOL’s Earth Science Module.

Modeling Soil Water Dynamics with Time-Variable Soil Hydraulic Properties

A. Schwen[1], G. Bodner[2], A. Schnepf[3], D. Leitner[3], G. Kammerer[1], and W. Loiskandl[1]

[1]Institute of Hydraulics and Rural Water Management, Univ. Natural Resour. Appl. Life Sci., BOKU, Wien, Austria
[2]Institute of Agronomy and Plant Breeding, Univ. Natural Resour. Appl. Life Sci., BOKU, Wien, Austria
[3]Institute of Soil Science, Univ. Natural Resour. Appl. Life Sci., BOKU, Wien, Austria

Modeling soil water dynamics requires an accurate description of soil hydraulic properties, i.e. the retention and hydraulic conductivity functions. Generally, these functions are assumed to be unchanged over time in most simulation studies. In this paper, we implemented temporal changes in the soil hydraulic properties in a Richards’ equation simulation of soil water dynamics. Based on ...

Laminar Thermal Mixing in Coating Flows

A. Haas[1], M. Scholle[1], A. Aksel[1], H.M. Thompson[2], R.W. Hewson[2], and P.H. Gaskell[2]

[1]Department of Applied Mechanics and Fluid Dynamics, University of Bayreuth, Bayreuth, Germany
[2]School of Mechanical Engineering, University of Leeds, Leeds, United Kingdom

Heat transfer in a plane shear flow configuration consisting of two infinitely long parallel plates is considered. In laminar flows over undulated substrates eddies can be generated due to the kinematical constraints. A closed form analytical solution for the velocity field, based on lubrication theory as well as a semi-analytic solution for the temperature field is derived for the creeping flow. ...

Modeling of Viscous Fingering

E. Holzbecher[1]

[1]Georg-August University, Göttingen, Germany

Viscous fingering is a topic of interest since the beginning of computational fluid dynamics. Here we focus on the classical constellation of miscible displacement, as it has been investigated in Hele-Shaw cells. A temperature or salinity front is entering with a fluid that has a different viscosity. The pure 1D flow is destabilized by the Saffman-Taylor instability. Using COMSOL Multiphysics® ...

Numerical Simulation of the Functional Electromagnetic Stimulation of the Human Femoral Bone using COMSOL

Y. Haba[1], W. Kröger[2], H. Ewald[2], R. Souffrant[1], W. Mittelmeier[1], and R. Bader[1]

[1]Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, University of Rostock, Rostock, Germany
[2]Institute of General Electrical Engineering, University of Rostock, Rostock, Germany

In the present study we determined the relative conductivities and permittivities of fresh cortical and cancellous bone measuring human femoral heads in different slices of 1 mm thickness. The identified conductivities of human trabecular bone are used for the electromagnetic field simulation by means of COMSOL using a Micro-Computed Tomography (Micro-CT) model. The calculated model depends on a ...

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