The Seventh International Symposium on Physics of Fluids (ISPF7) was held in Guiyang, China from June 12, 2017 to June 15, 2017. It attracted more than 150 researchers around the world to present their research progress in the area of computational and experimental fluid dynamics, and applications of fluid mechanics. Many advances in the fundamental research of computational and experimental fluid dynamics and practical applications in industry have been reported in the symposium. Specifically, the topics include turbulent flow, flow stability, flow visualization and measurement, fluid-structure interaction, aeroelastic analysis, supersonic and hypersonic flow analysis and experiments, applications of micro flow, multiphase flow and cavitation flow, lattice Boltzmann method and its applications, adaptive mesh refinement, unstructured mesh solvers, immersed boundary method and its applications, and so on.
This special topic represents a selection of the papers presented in the symposium. It covers advances in the theoretical, experimental, and numerical studies of fluid mechanics. In the theoretical study, Poungthong et al.1 presented a Padé approximation for the normal stress differences in large-amplitude oscillatory shear flows, which improves the existing solutions. In the experimental and turbulent study, through Particle Image Velocimetry (PIV) measurement, Jia et al.2 examined the transition process in a boundary layer on a rotor blade under the impingement of an inlet guide vane (IGV) wake, which is an important step toward understanding the transition mechanism. Zhang and Xiao3 investigated the process of single-particle dispersion in the compressible turbulent flows by using direct numerical simulation, where the effect of the Stokes number and Mach number on the particle dispersion is studied and analyzed in detail. Jiang et al.4 numerically investigated the fully developed spanwise rotating turbulent channel flow by using large-eddy simulation (LES), in which the performance of several eddy viscosity models was tested. Li et al.5 investigated the self-assembly of micro-particles under the magnetic field experimentally and numerically, which provides guidance on controlling the formation of self-assembly non-magnetic particles and technical support for the design and fabrication of micro/nano-materials. In the topic of computational fluid dynamics (CFD), many new numerical approaches are developed, which provide efficient tools for the study of physics in fluids. Lei and Li6 presented a new non-oscillatory energy-splitting conservative algorithm for computing multi-fluid flows in the Eulerian framework. Numerical experiments demonstrate that nonphysical oscillations can be suppressed around material interfaces substantially by this algorithm. Yuan et al.7 proposed a modified level set method for simulation of multiphase flows with a large density ratio and high Reynolds number, which can guarantee the overall mass conservation during the simulation. Yang et al.8 presented an implicit DVM (discrete velocity method) with the memory reduction technique, which greatly reduces computational effort and memory cost in the simulation of flows in all regimes by solving the steady discrete velocity Boltzmann equation (DVBE) as compared to the existing DVM solvers. Wu et al.9 presented a nodal discontinuous Galerkin-lattice Boltzmann method (NDG-LBM), which extends the application of LBM for complex geometry. In the application of CFD for the study of fluid flows, Zhang and Cao10 investigated the non-Boussinesq effect in the thermal convection in an air-filled horizontal concentric annulus by using the variable property-based lattice Boltzmann flux solver (VPLBFS), which reveals the complicated flow instability behavior under non-Boussinesq conditions and its tight association with heat transfer characteristics. Zheng et al.11 presented a concept study on supersonic flow control using a nanosecond pulsed plasma actuator by means of numerical simulation.
On behalf of the organizing committee, we wish to take this opportunity to thank each of the authors for their contribution to this special topic. We would like to thank Peking University, Nanjing University of Aeronautics and Astronautics, and American Institute of Physics (AIP) for their sponsorship of this symposium. In particular, we wish to thank Professor Jeffrey Giacomin and Professor Nhan Phan-Thien for their support to the symposium and this special topic in Physics of Fluids.