PD Dr. Yan Jin
Eissendorfer Str. 38, bulding O, Room 3.019
Telephone +49 40 42878-4644
E-Mail: PD Dr. Jan Yin.
Turbulence modelling, simulation, and control
A turbulence model with high accuracy and low computational cost, see Jin (2019), has been developed through the DFG-Heisenberg program (299562371). The developed turbulence model has higher accuracy than classic LES and RANS models when the same mesh resolution is used. It is particularly suitable for simulating complex turbulent flows in industry, e.g., flows in turbomachinery (Jin 2020), see Fig. 1. We are also interested in the techniques of controlling turbulence and reducing the corresponding irreversible losses, see Jin & Herwig (2014) and Li, et al. (2021) as examples.
Convection in porous media
Porous media are an important material in nature and industry. Convection in porous media receives a lot of attentions in recent years with the emergence of some new engineering applications, e.g., long term storage of CO2 in deep saline aquifers, thermal energy storage systems using stones/bricks as storage materials, etc. Based on deep investigation of physics, we try to develop efficient and accurate macroscopic models for predicting losses and heat/mass transfer rate in porous media (Fig. 2), see details in Jin, et al. (2015; 2017), Uth, et al. (2016), Kranzien & Jin (2018), Rao, et al. (2020) and Gasow, et al. (2020) for the details of this research. This research is funded by the DFG (408356608).
Flows in biological and physiological processes
Bio-fluid mechanics is an interdisciplinary study which is located at the interface of fluid mechanics and biology. This is a new and promising research field. We are studying the digestion process in human-stomach using a CFD method, see Li & Jin (2021). We have also investigated the “Magenstrasse” based on the numerical results (Fig. 3), see Li, et al. (2021). This research is funded by the Chinese Scholar Council (CSC). In another research topic, we are investigating the flow and particle transportation in a human’s respiratory system (Fig. 4).
|Title: Mixing and emptying of gastric contents in human-stomach: A numerical study.|
|Written by: Li, C.Y.; Xiao, J.; Chen, X.D.; Jin, Y.|
|in: <em>J. Biomech.</em>. (2021).|
|Volume: <strong>118</strong>. Number: (110293),|
Abstract: Stomach is one of the most important organs in human gastro-track. To better understand the operation of human-stomach, the process of mixing and emptying of gastric contents is simulated using a numerical method. The numerical results confirm that a fast pathway is located close to the lesser curvature of the stomach when water is emptied. However, this fast pathway doesn’t exist when the gastric contents are composed of water and food boluses with different properties. The muscle contractions enhance the mixing of light food boluses and water, while they have limited effects on heavy food boluses. As a result, the foods are distributed in layers; heavy food boluses are located in the bottom layer. Besides the gastric motility and high viscosity of foods, the food matrix made of heavy food particles is also important to the formation of the Magenstrasse (stomach road). The food matrix and the zone of wrinkles behave like a porous medium which has higher flow resistance to the light food particles than to the water, leading to faster emptying of water. The water is emptied along the stomach wall since the flow resistance in the stomach wrinkles is smaller than the one in the food matrix. This mechanism is supported by the numerical results, while it might interpret the phenomena observed in the experiments.