Group of Impact Dynamics and Coupling Effects
Our lab addresses a variety of topics in the general area of mechanics of materials and structures coupled with its working or processing environments, which include the interaction between the structure and fluid, the interaction between the structure and thermal field, and the interaction between the materials and shock loading. The overarching goal is the solution of technological problems through the integration of analytical, computational and experimental techniques. Depending on the specific problem at hand, we study and apply concepts and methods of solid mechanics, fluid mechanics, heat transfer and materials sciences.
|Title:||Study of Characteristics of Cloud Cavity Around Axisymmetric Projectile by Large Eddy Simulation|
|Author:||Yu XX(于娴娴); Huang CG(黄晨光); Du TZ(杜特专); Liao LJ(廖丽娟); Wu XC; Zheng Z; Wang YW(王一伟)|
|Reprint Author:||Wang, YW (reprint author), Chinese Acad Sci, Inst Mech, Key Lab Mech Fluid Solid Coupling Syst, 15 Beisihuanxi Rd, Beijing 100190, Peoples R China.|
|Abstract:||Cavitation generally occurs where the pressure is lower than the saturated vapor pressure. Based on large eddy simulation (LES) methodology, an approach is developed to simulate dynamic behaviors of cavitation, using k - mu transport equation for subgrid terms combined with volume of fluid (VOF) description of cavitation and the Kunz model for mass transfer. The computation model is applied in a 3D field with an axisymmetric projectile at cavitation number sigma = 0.58. Evolution of cavitation in simulation is consistent with the experiment. Clear understanding about cavitation can be obtained from the simulation in which many details and mechanisms are present. The phenomenon of boundary separation and re-entry jet are observed. Re-entry jet plays an important role in the bubble shedding.|
|Journal Title:||JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME|
- Hydrodynamics & Fluid-Structure Coupling
- Thermal Structures
- Impact Dynamics
• Unsteadycavitating flow mechanism
• Mechanism and dynamic loadings of collapse of cavitation bubbles around the high-speed underwater vehicle in the out-of-water process
• Fluid-structurecoupling of high-speed vehicle during underwater launching process
• Maneuverability of new pattern vehicles in the underwater and surface navigation conditions
• Fluid-structure coupling of the large-scale flexible airship.
• Coupling effects and thermal-fluid-structure interaction in high-speed flights and propulsion systems
• Cellular sandwich structures, light-weight structures and multi-functional design
• High temperature materials and structures; Structural integrity at extremely severe and high temperature environments
• Thermal effects, shock effects and failure mechanisms when high power laser interaction with matter
• Functional materials.
• Brittle materials.
• Metallic materials.
Ultimately, we strive to expand existing and create entirely new and general classes of laser processing techniques that open up novel research opportunities and technologies within our group and for the field as a whole.
- High density laser driven platform
- High-speed impact platform for structures
- High-speed Impact Material Test System (HIMTS)
This platform dedicates to the research of some transient energy transformation process (high-speed deformation of material, laser shock peening and explosive underwater etc.). The high density laser is used as the driven sources which can generated a very high amplitude (up to 5 GPa) pressure pulses in very short time (about 20 ns). A variety of high spatial and temporal resolution test method including PVDF (Polyvinylidene Fluoride), PDV (Photonic Doppler Velocimetry) and high-speed camera etc is adopted to capture the transient process. The main experimental system includes:
• Laser shock peening system
• Dynamic material property system
• Underwater explosive system
HIMTS has an ability to obtain the dynamic stress-strain curve of materials from 102s-1 to 5×104s-1. The diameters of input and output bar are 8mm, 16mm and 25mm. The automatic control system gives 1% accuracy and 250 m/s limit to launch speed. The experimental temperature is from -150~1000 ℃