TAILIEUCHUNG - Body parameters with application of optimal differential variation method in super cavity model

When a slender body moves very fast through water at sufficient speed the cavity phenomena is happened. In a cavity model the bodys lengths and cavitator diameter are determined by the differential variation optimal method so that the velocity of body is maximum. | Vietnam Journal of Mechanics, VAST, Vol. 38, No. 4 (2016), pp. 267 – 278 DOI: BODY PARAMETERS WITH APPLICATION OF OPTIMAL DIFFERENTIAL VARIATION METHOD IN SUPER CAVITY MODEL 1 Institute Tran Thu Ha1,2,∗ , Nguyen Anh Son3 , Duong Ngoc Hai1 of Mechanics, Vietnam Academy of Science and Technology, Hanoi, Vietnam 2 VNU University of Engineering and Technology, Hanoi, Vietnam 3 National University of Civil Engineering, Hanoi, Vietnam ∗ E-mail: tran thuha1@ Received September 16, 2015 Abstract. When a slender body moves very fast through water at sufficient speed the cavity phenomena is happened. In a cavity model the bodys lengths and cavitator diameter are determined by the differential variation optimal method so that the velocity of body is maximum. Keywords: Super cavity, Runge-Kutta methods, data assimilation. 1. INTRODUCTION In hydrodynamics applications cavitation is the appearance of vapor bubbles and pockets inside homogeneous liquid medium. This phenomenon occurs because the pressure is reduced to the vapor pressure limit. We will study super cavity appearing by the very fast movement of slender body in water that makes uncontrolled gun-launched slender body. Except the body head called by cavitator is directly touching with water, the gas layer can be covered partial or full body depending on the design of body form. The body rotates about its nose. In this paper for simple calculation we choose cavitator formed by the plate disk with diameter (see Fig. 1). The body is consisted of two parts: the cone top and cylinder part with the diameter d. In the super cavity model the following assumptions are (see [1]): - The motion of the projectile is confined to a plane; - The slender body rotates about its nose; - The effect of gravity on the dynamics of this body is negligible; - The motion of the slender body is not influenced by the presence of gas, water vapor or water drops in the cavity; c 2016 Vietnam Academy of Science .

• Vật lý
• Vietnam Journal of Mechanics
• Body parameters with application
• Optimal differential variation method
• Super cavity model
• Slender body moves
• The differential variation optimal method
• Dang Dinh Ang
• Nonlinear analysis and mechanics
• Dynamic problems involving stationary cracks
• The Wiener Hopt technique
• Dual integral equations
• Dual integrals in non linear fracture mechanics
• Non linear fracture mechanics
• Energy release rate
• Discuss the obtained
• The alpha finite element method (αFEM)
• Solid mechanics using triangular and tetrahedral elements
• Suitable computational cost
• NS FEM makes
• The upper bound property
• Non linear constitutive problems in solid mechanics
• Non linear constitutive problems
• Languages Gibian and special operators
• The application FEM
• Betts miller janjic convective parameterization scheme
• H14 31 model to forecast heavy rainfall in Vietnam
• Betts Miller Janjic
• Three rain seasons
• Manufacturing dry mixed cement mortar
• High compressive strength
• High flexural strength
• Low shrinkage and high watertightness for restoration
• Damaged hydraulic structures in Vietnam
• Standard gradient models and crack simulation
• Standard gradient models
• The propagation of cracks
• Damage mechanics and crack simulation
• The interaction between two parametric excitations
• The second and third degrees
• The asymptotic method of nonlinear mechanics
• Dynamic system governed
• Comparison of two hydrological model simulations
• Nam and Xinanjiang for Nong Son catchment
• The Central Vietnam
• The runoff components
• 3 D numerical simulation
• The tidal circulation
• The gulf of Tonkin
• The kinetic energy distribution
• Duality in the analysis of responses to nonlinear systems
• The analysis of responses
• The original nonlinear systems
• The study of nonlinear mechanics
• Aerodynamics of a wing in surface effect ship
• Theory and experiment
• Wing in surface effect ship
• The aerodynamic characteristics
• The Institute of Mechanics
• The error estimate
• The convergence rate for h
• p refinement
• The finite element analysis
• Three dimensional elastostatic mechanics problems
• Some initial experimental results
• Free water layer formation in horizontal pipes
• Water layer formation
• Hanoi Institute of Mechanics
• Bending vibration of beam elements under moving loads
• Considering vehicle braking forces
• Fluctuations of structures
• Beam elements according
• Continuous element for vibration analysis
• Thick shells of revolution
• Continous Element Method
• Finite element solutions
• Natural frequencies and harmonic responses
• Cast3m implementation of the extended finite element method
• The extended finite element method for cohesive crack
• Quasi brittle materia
• The proposed implementation
• The displacement discontinuities
• Buckling analysis of simply supported composite laminates subjected
• In plane compression load
• A novel mesh ffree method
• Alternative numerical technique
• Mesh free method
• A three story building
• Hedge algebras based fuzzy controller
• The structural system
• The El Centro earthquake
• Three story building against earthquake
• Laminar separation phenomenon combining with numerical calculations
• The turbulent separation
• The laminar separation
• Experimental study on mechanical properties
• Three phase polymer composite reinforced
• Glass fibers and titanium oxide particles
• Polymer composite reinforced
• Three phase composite
• Dynamic characteristics of elastically supported beam subjected
• A compressive axial force and a moving load
• The implicit Newmark method
• The Galerkin finite element method
• The axial force
• Eccentrically stiffened functionally graded plates and shallow shells
• Von Karman Donnell sense
• The formulation of governing equations
• The classical shell theory
• Mathematical modelling and control of the evolution
• Dynamic systems interacting with medium
• Mathematical modeling evolutional systems interacting
• Two conjugate mechanical subsystems
• Evaluating structural safety based on fuzzy set theory
• Evaluating structural safety
• The fuzzy reliability
• Simple beam structure