Modeling of Ultrasonic Transducers and Ultrasonic Wave Propagation for Commercial Applications Using Finite Elements with Experimental Visualization of Waves for Validation - new
D. R. Andrews
Cambridge Ultrasonics, Over, UK
Finite element (FE) modelling of ultrasonic propagation using COMSOL Multiphysics® simulations can be used to create images of waves. Unfortunately, in time-stepping solutions, it is possible for numerical instabilities to grow large and dominate the solution adversely. Any design of transducer that is based upon poorly-configured FE models is unlikely to perform as expected and will almost ...
T. Gasch , A. Ansell ,
 KTH Royal Institute of Technology, Stockholm, Sweden
An extension of the Solid Mechanics interface in COMSOL Multiphysics® is presented to analyze localized deformations of quasi-brittle materials, for example cracking in concrete. This is achieved by implementing an isotropic damage mechanics constitutive law, which is combined with both a local and a non-local regularization technique to ensure mesh objectivity. The implementation is made using ...
Y. T. Habtemichael, R. T. Kiflemariam, H. R. Fuentes
Department of Civil & Environmental Engineering, Florida International University, Miami, FL, USA
Department of Mechanical & Materials Engineering, Florida International University, Miami, FL, USA
Seawater intrusion into coastal aquifers is usually modeled by using transport models that include account for the effect of variable-density on flow. Variable-density models can be validated with the Henry and Elder benchmark problems. However, when mixed convective flow is simulated under variable density conditions, it is susceptible to physical and numerical instabilities. The purpose of ...
Multiphysics Modelling of Standing Column Well and Implementation of Heat Pumps Off-Loading Sequence
A. Nguyen, P. Pasquier, D. Marcotte
 Department of Civil, Geological and Mining Engineering, École Polytechnique de Montréal, Montréal, QC, Canada
A fully coupled multiphysics model involving heat transfer and groundwater flow within a SCW and its surrounding ground was implemented in COMSOL Multiphysics 4.2a with MATLAB to simulate a 24-hour heating operation. The heat pumps were modeled using interpolation functions thereby allowing the effect of the pumped water temperature on the capacity and coefficient of performance of the heat ...
Full Coupling of Flow, Thermal and Mechanical Effects in COMSOL Multiphysics® for Simulation of Enhanced Geothermal Reservoirs
D. Sijacic, P. Fokker
TNO, Utrecht, The Netherlands
The effective modeling of enhanced geothermal systems (EGS) requires the coupling of geomechanics, fluid flow and thermal processes. An understanding of the complete system with these coupled processes is vital, not just for reservoir stimulation targeted at enhancing reservoir performance, but also for the understanding, prediction and prevention of induced seismicity. Thermal effects however ...
C. K. C. Arruda , A. A. Silveira , L. C. R. Vieira , F. C. Dart ,
 CEPEL, Rio de Janeiro, RJ, Brazil
High Voltage Direct Current transmission (HVDC) is a suitable alternative for long distance transmission. During the years, the use of this technology has been increasing, which is one of the several reasons to improve methodologies in HVDC grounding systems. Unlike the usual approach in AC, a HVDC grounding system is distinguished by its operating procedures, which is, when it is configured ...
University of Dayton, Dayton, OH, USA
Geothermal heat pumps use the earth as a heat source and sink via a ground heat exchanger (GHX) that consists of a network of buried heat exchange pipes, which can either be installed in vertical boreholes or in shallow horizontal trenches or excavations. The main goal in GHX design is to determine the minimum length of pipe needed to provide adequate fluid temperatures to heat pumps over their ...
R. Caulk, J. McCartney, E. Ghazanfari
University of Vermont, Burlington, VT, USA
University of Colorado, Boulder, CO, USA
In this study, a model of in-situ geothermal energy piles was constructed using COMSOL Multiphysics® software. Geothermal energy piles serve two purposes, first to transfer building load into the subsurface, but also to extract thermal heat from surrounding soils. This is achieved using a heat pump coupled with embedded heat exchangers. As a result, a multiphysics problem is introduced - heat ...
M. Karlsson , J. Yannie ,
 Chalmers University of Technology, Gothenburg, Sweden
In this work a modified anisotropic creep model with structure for soft soils was implemented by using the Physics Builder. The model is validated against boundary value laboratory test such as undrained tri-axial tests and CRS (constant rate of strain) tests. The implemented user-defined MAC-s constitutive model seems to capture many of the important behaviors seen in soft soils.
Georg-August University, Göttingen, Germany
Energy piles, i.e. heat exchangers located within the foundation piles of buildings, are used for heating of cooling purposes. Although the absolute values of deformations and temperature gradients are low or moderate, the entire setting can be influenced by thermo-hydro-mechanical coupling. The fluctuating thermal regime may affect the deformation of pile and surrounding ground as effect of ...