Effect of Colon Stiffness on Peristaltic Transport of Chyme: a Numerical Simulation
M. Pourjafar1, A. Kuchumov2, K. Sadeghy3; 1Department of Mechanical Engineering, University of Tehran, Tehran, Iran; 2Perm National Research Polytechnic University, Perm, Russia; 3Center of Excellence in Design and Optimization of Energy Systems (CEDOES), School of Mechanical Engineering, University of Tehran, Tehran, Iran
Abstract
It is a well-established fact that stiffness of the colon is altered during the occurrence of certain diseases such as Crohn. This can affect the magnitude of the radial and axial forces generated by colon muscles. Since the periodic forces generated by these muscles play a key role in chyme transport (through the generation of peristaltic waves) it is speculated that variation of colon stiffness may disrupt peristaltic waves thereby further complicating the disease that caused it or giving rise to new diseases. In the present work, we have numerically investigated the effect of colon stiffness on the transport of digested food. For ease of analysis we have modelled the colon as a two-dimensional channel. For the same reasoning, the chime is assumed to be a Newtonian fluid. More importantly, the viscoelasticity of the colon is modelled using the Carpenter linearly-viscoelastic solid model. For numerical simulations, we have relied on the artificial compressiblity method (ACM). The main objective of this study is to investigate the roles played by the colon wall elasticity, viscous damping, and longitudinal tension on the mass flow rate and wall shape (which may not necessarily follow the peristaltic waveform). Converged results could be obtained at moderate Reynolds numbers for arbitrary wavelengths and amplitude ratios over a wide range of working parameters. The results demonstrate the crucial role played by the stiffness of the colon on the chyme transport.
Funding: The reported study was funded by RFBR and INSF, project number 20-58-56014.
Keywords: Peristaltic flow, colon, stiffness, chyme, ACM method, Carpenter solid model.
Speaker
Mohammad Pourjafar
Department of Mechanical Engineering, University of Tehran
Iran
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