THE INTERACTION OF A SHOCK WAVE WITH THE BOUNDARY LAYER IN A REFLECTED SHOCK TUNNEL

The influence of anontotal reflection on the interaction of areflected shock wave withthe boundary layer in a refleeted Shock lunnel has been investigated The calculatingmethod of the velocity,the tempeture and the Mbch number profiles in the boundary layerin reflected shock fixed coordinates has been obtained To account for equilibrium real gaseffects of nitrogen the numerical results show that the minimum Mach number in theboundary layer has been movedfrom the wall into the boundary layer with the increasing ofthe incident shock Mach number.The minimum Mach number,the shock angle in thebifurcated foot and the jet velocity along the wall to the end plate are reduced owing to theincreasing of the area of nozzle throat.The numerical resulls are in good agreement withmeasurements.     

FORCED VIBRATIONS OF ELASTIC SHALLOW SHELL DUE TO THE MOVING MASS

This paper discusses the forced vibrations of the elastic shallow shell due to the movingmass by means of the variational method. In the text mentioned above a series of problemssuch as the forced vibrations,resonance conditions and critical speed and so forth.     

SOLVING THE VELOCITY PARAMETER OF THE 2-D WAVE INVERSE PROBLEMS WITH THE INTEGRATION-CHARACTERISTIC METHOD

For the 2-D wave inverse problems introduced from geophysical exploration,in thispaper,the author presents integration-characteristic method to solve the velocityparameter,and then applies it to common shotpoint model data,in noise-free case.Theaccuracy is quite good.     

DYNAMIC RESPONSE OF PLATES ON ELASTIC FOUNDATIONS DUE TO THE MOVING LOADS

This paper discusses the dynarmic response of thin plates on the elastic foundations dueto the moving loads by means of the variational calculus. In the text we take the mass ofmoving loads into account. treat a series of questions such as the forced oscillatons,theinfluence surfaces of the flexions and the influence surfaces of the inner forces,resonanceconditions and critical speed and so forth.     

THE VELOCITY OF SAND PARTICLES RELATIVE TO WATER AND THE VARIATI0N 0F FLUCTUATION VELOCITY DUE TO THE CONCENTRATION OF SUSPENDED SAND PARTICLES

In this paper.we discuss three fundamental problemsof the theory of suspended sand particles based on thetheory of fluid dynamics.They are:(1)the relative ve-locity of sand particles to the surrounding fluid in theturbulent flow.(2) the variation of the velocity fluc-tuation of the fluid when the suspended sand particlesexist,(3)the profile of the vertical distribution ofthe concentration of the suspended sand particles in two-dimensional uniform steady channel flow and the modifi-cation of usual diffusion theory.The results of our.theoretical analysis are somewhat different from the cor-responding expressions in the textbooks of hydraulicsand river mechanics.     

THE POWER FLOW AND TRAVELING WAVE APPROACH TO THE VIBRATION ANALYSIS OF BASE-ISOLATED MULTI-STOREY BUILDINGS

The receptance approach to periodic structure theory is applied to studythe wave propagation and vibration power flow into a base-isolated multi-storeybuilding due to horizontal harmonic ground motion.Multi-storey buildings andlaminated rubber bearings have been modeled as periodic systems in this paper.Although the simplified model considered is quite simple,it is expected that it will bringforth the key differences between continuous and a single freedom systems.The resultsindicate that the isolation effectiveness depends on not only the number of storeys ofthe laminated rubber bearings but also the frequency characteristics of thesuperstructure.     

SELF-EXCITED VIBRATION OF A CONTROL VALVE DUE TO FLUID–STRUCTURE INTERACTION

In this paper, the mechanism causing self-excited vibration of a piping system is determined using a dynamic model which couples the hydraulics of a piping system with the structural motion of an air-operated, plug-type automatic control valve. In the dynamic model developed, the structural system consists of a valve spring–mass system, while the fluid system consists of a pump, upstream piping, control valve and downstream piping. The coupling between the structural and the fluid systems at the control valve is obtained by making the fluid flow coefficient at the control valve to be a function of valve plug displacement, and by making the valve plug displacement to be a function of fluid pressure and velocity. The dynamic model presented in this paper, for the first time, considers compressibility of the fluid in both the upstream and downstream piping. The dynamic model presented was benchmarked against in situ measurements. The data used for the benchmarking are provided in the paper. A review of the numerical results obtained indicates that the self-excited vibration occurs due to the coincidence of water hammer, acoustic feedback in the downstream piping, high acoustic resistance at the control valve, and negative hydraulic stiffness at the control valve.     

ON THE APPLICATION OF ADI METHOD TO NUMERICAL SIMULATION OF THE MARANGONI CONVECTION CONTROLLING IN LIQUID BRIDGE MODEL

An ADI scheme is suggested to simulate the Marangoni convection controlling with emphasis on investigating application of the technique numerically. Numerical experiments conducted in the present paper turn out both successful and efficient. Hence, ADI scheme is expected to be extended to the study of other convection processes related to material manufacturing.     

APPLICATION OF THE HYPERSINGULAR INTEGRAL EQUATIONS METHOD TO THE INTERACTION BETWEEN TWO PARALLEL PLANAR CRACKS IN 3-D ELASTICITY

By using the analytic theory of hypersingular integral equations in three-dimensional fracture mechanics, the interactions between two parallel planar cracksunder arbitrary loads are investigated. According to the concepts and method of finite-part integrals, a set of hypersingular integral equations is derived, in which theunknown functions are the displacement discontinuities of the crack surfaces. Then itsnumerical method is proposed by combining the finite-part integral method with theboundary element method. Based on the above results, the method for calculating thestress intensity factors with the displacement discontinuities of the crack surfaces ispresented. Finally, several typical examples are calculated and the numerical resultsare satisfactory.     

ANALYSIS TO THE STRESS CONSTRUCTION AT THE VICINITY OF CRACK TIP FOR MODE I FRACTURE IN 3-D STATE USING FINITE ELEMENT METHOD

The stresses and strains are calculated for CT specimen of power hardening material in 3-D deformation state using ADINA finite element program, and the stress distribution at the vicinity of crack tip for Mode Ⅰ fracture is analysed according to the results of calculation. It is found that the expression of stress can be written as the form of separation of variables of r and θ, then the function off can be expanded in Laurant series. It is still found that the three normal stresses have the same order of magnitude. The conclusions offer two suppositions to obtain the theoretical expression of stress at the vicinity of crack tip for Mode Ⅰ fracture with good ground, and the procedure of solution will be greatly simplified.     

FINITE ELEMENTAN ALYSIS FOR THE UNSTEADY NEARSHORECIR CULATION DUE TO WAVE－CURRENT INTER－ACTION（I）──NUMERICAL MODEL

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FINITE ELEMENT ANALYSIS FOR THE UNSTEADY NEARSHORE CIRCULATION DUE TO WAVE－CURRENT INTERACTION（II）──TWO－STEP EXPLICIT FINITE ELEMENT METHOD

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VARIATIONAL PRINCIPLE OF HYBRID ENERGY AND THE FUNDAMENTALS OF 3-D LAMINATE THEORY—A NEW APPROACH FOR THE ANALYSIS OF INTERLAMINAR STRESSES IN COMPOSITE LAMINATES

This paper discusses the discuntinuity of stresses and strains at interlaminar surfaces of the eomposne laminate and presents a 3-D laminate theory for composite materials. This paper also presents a new type of clastic energy based on the globally continuous variables in laminates, different from the traditional potemial energy and complementary energy. Then. a variational principle corresponding to the 3-D laminate theory is developed. The theory and the principle could be a basis of verifying the 2-D lamimte theory and deterplining the interlaminar stresses mear the free edges.     

EFFECTS OF TENSOR CLOSURE MODELS AND 3-D ORIENTATION ON THE STABILITY OF FIBER SUSPENSIONS IN A CHANNEL FLOW

IntroductionFlowoffibresuspensionshasbeenveryfamiliarinmanyindustrialfields.Fibreadditivesplayanimportantroleindragreductioninmanytypesofflow[1- 3].Inthesuspensions,somebehavioroftheflowmaybealteredbythefibres.Oneoftheimportantexamplesisthehydrodynamicsta…     

STUDY OF AXIAL VELOCITY IN GAS CYCLONES BY 2D-PIV, 3D-PIV, AND SIMULATION

The axial velocity distribution in a gas cyclone has been examined with two-dimensional particle image velocimetry （2D-PIV） and three-dimensional particle image velocimetry （3D-PIV） experiments in this study. Due to the limitation of 2D-PIV configuration, the contamination generated by the strong tangential velocity in the cyclone can be registered in the axial velocity detected by 2D-PIV. Efficient methods are proposed in this work to remove this contamination. The contamination-removed 2D-PIV data agree well with 3D-PIV results. The distributions of the axial velocity are also computed by the Reynolds stress model （RSM） and verified using the PIV experimental results. Reasonable agreements are obtained.     

NUMERICAL ANALYSIS OF LAMINAR MIXED CONVECTION HEAT TRANSFER OF THE Al2O3–H2O NANOFLUID IN A SQUARE CHANNEL

Journal of Applied Mechanics and Technical Physics - In this study, the Al2O3–H2O nanofluid flow through a duct with a square cross section under a constant heat flux is simulated using a...