Newsletter  2023.10  Index

Theme : "AJK FED 2023" Preface Hyun Jin PARK, Shoichi MATSUDA, Chungpyo HONG Evaluation of railway vehicles' resistance against strong crosswinds and its application for safe railway operation Yayoi MISU (East Japan Railway Company) Order within Turbulence Susumu GOTO (Osaka University), Yutaro MOTOORI (Osaka University) LES/Lagrangian-particle-simulation of a Reactive Turbulent Planar Jet Jiabao Xing (Nagoya University)，Tomoaki WATANABE (Nagoya University)，and Koji NAGATA (Kyoto University) Unsteady Characteristics of Tip Leakage Vortex Cavitation in the Occurrence of Cavitation Instability in Liquid Rocket Inducer Koki TAMURA (Tohoku University)，Yuto NAKURA (Tohoku University), Satoshi KAWASAKI (Japan Aerospace Exploration Agency), Yuka IGA (Tohoku University) Water Condensation in PEMFCs at Nano-scale: Insights through Lattice DFT simulations Clint John Cortes OTIC (The University of Tokyo), Masazumi ARAO (FC-Cubic), Masashi MATSUMOTO (FC-Cubic), Hideto IMAI (FC-Cubic), Ikuya KINEFUCHI (The University of Tokyo) Reconstruction of Fluid Stress Field from Flow Birefringence using Physics-Informed Convolutional Encoder-Decoder (PICED) Daichi IGARASHI (Tokyo University of Agriculture and Technology), Shun MIYATAKE (Tokyo University of Agriculture and Technology), Jingzu YEE (Tokyo University of Agriculture and Technology), Yoshiyuki TAGAWA (Tokyo University of Agriculture and Technology) Determination of Permeability in the Volume Penalisation Method with a Smooth Mask Function Taichi TSUJIMOTO (Osaka University), Yuta NAKAO (Osaka University), Takuya TSUJI (Osaka University), Toshitsugu TANAKA (Osaka University), Kimiaki WASHINO (Osaka University)

 

Determination of Permeability in the Volume Penalisation Method with a Smooth Mask Function

Taichi TSUJIMOTO， Yuta NAKAO， Takuya TSUJI， Toshitsugu TANAKA， Kimiaki WASHINO Osaka University

Abstract

Fluid-particle flows are frequently encountered in many engineering applications. However, our knowledge today about fluid-particle interactions is far from complete. The Volume Penalisation (VP) method is increasingly popular for Particle Resolved Direct Numerical Simulation (PR-DNS) where solid particles are modelled as permeable bodies with low permeability. In the VP method, fluid and solid (particle) are distinguished by a mask function. A smooth mask function with finite interface thickness is sometimes employed rather than a traditional sharp mask function to suppress numerical oscillation. In this case, however, the permeability should be determined with extra care otherwise the simulation results may become dependent on the interface thickness. In this work, a new model is proposed to determine the permeability in the VP method with a smooth mask function. It is “active” in the sense that the permeability is dependent on the flow field. The model is theoretically derived to reduce the model error particularly when the pressure gradient and/or external forces are large. The theory is based on the momentum equation simplified with the order-of-magnitude argument. Several test simulations of fluid-particle flows are performed to discuss the validity of the proposed model. In the simulation of a sphere moving towards a wall, the fluid force acting on the particle as well as the pressure increase at the particle-wall gap are accurately captured. In the simulation of suspension under simple shear, the relative viscosity is accurately estimated at high particle concentration. In addition, the proposed model is used to simulate complex fluid flow through packed ellipsoid and cuboid particles. It is found that the shape effect becomes more significant when the particle concentration is high.

Key words

Fluid-particle flow, Particle Resolved Direct Numerical Simulation (PR-DNS), Volume Penalisation method, Permeability

Figures

Figure 1. Schematic of a sphere moving towards a wall.

Figure 2. Error of fluid force acting on a particle.

Figure 3. (a) Flow through packed non-spherical particles and (b) non-spherical particles represented by superquadric function.

Figure 4. fluid force acting on the ellipsoid and cuboid particles.