4,081 research outputs found
Verification and Validation of Numerical Modelling Approaches Pertinent to Stomach Modelling
The digestive system is vital to the human body. Over many decades, scientists have been
investigating the food breakdown mechanisms inside the stomach through in vivo human and animal
studies and in vitro experiments. Due to recent improvements in computing speed and algorithm
development, computational modelling has become a viable option to investigate in-body processes.
Such in silico models are more easily controlled to investigate individual variables, do not require
invasive physical experiments, and can provide valuable insights into the local physics of gastric flow.
There is a huge potential for numerical approaches in stomach modelling as they can provide a
comprehensive understanding of the complex flow and chemistry in the stomach. However, to make
sure the numerical methods are accurate and reliable, rigorous verification and validation are
essential as part of model development. A significant focus of this thesis was on verifying and
validating the numerical modelling approaches pertinent to stomach modellin
Experimental and numerical studies of a centrifugal pump in cavitating conditions
In the presented study a special test pump with two-dimensional curvature blade geometry was investigated in cavitating and noncavitating conditions using different experimental techniques and a three-dimensional numerical model implemented to study cavitating flows. Experimental and numerical results concerning pump characteristics and performance breakdown were compared at different flow conditions. Appearing types of cavitation and the spatial distribution of vapor structures within the impeller were also analyzed. These results show the ability of the model to simulate the complex three-dimensional development of cavitation in a rotating machinery, and the associated effects on the performance
CFD analysis of industrial multi-staged stirred vessels
This paper presents tools for analysis of CFD results adapted for flows in multi-stage stirred vessels through out two industrial cases. Those tanks fitted with double-flow impellers are used first to cool down highly viscous resins and subsequently for indirect emulsification. Since the simulation of these processes in their whole complexity would be unrealistic, it considers single-phase flows without heat transfer. The result analysis in order to prove that the mixing and the circulation are effective is not usual; in these cases, the circulation and impeller numbers are not adapted. The average axial flow numbers are relevant of the circulation in the whole tank and of the connection between the flows produced by the propellers in the given configuration. The velocity profiles give relevant results, but are not sufficient whereas the particle tracking validates that the propellers do not work together in one case and do work together in a second one
Intrinsic Gaussian processes on complex constrained domains
We propose a class of intrinsic Gaussian processes (in-GPs) for
interpolation, regression and classification on manifolds with a primary focus
on complex constrained domains or irregular shaped spaces arising as subsets or
submanifolds of R, R2, R3 and beyond. For example, in-GPs can accommodate
spatial domains arising as complex subsets of Euclidean space. in-GPs respect
the potentially complex boundary or interior conditions as well as the
intrinsic geometry of the spaces. The key novelty of the proposed approach is
to utilise the relationship between heat kernels and the transition density of
Brownian motion on manifolds for constructing and approximating valid and
computationally feasible covariance kernels. This enables in-GPs to be
practically applied in great generality, while existing approaches for
smoothing on constrained domains are limited to simple special cases. The broad
utilities of the in-GP approach is illustrated through simulation studies and
data examples
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