An approach is proposed for calibrating hydraulic network models.The proposed procedure could reconcile results of all scenarios under various operation conditions and utilize prior information selectively.To achieve more accurate roughness with a faster processing,a hybridoptimization technique was developed to exploit advantages of genetic algorithm and active set method.The algorithm was applied to two sample networks,and resulting calibrated model was compared to counterpart in previous literature.The proposed approach was shown stable and estimated parameters were more accurate.

Roughness distributions of 1+1 dimensional noisy Kuramoto-Sivashinsky(KS) equation at steady states are obtained and compared with Kardar-Parisi-Zhang(KPZ) equation's with numerical simulation.It is shown that the scaling functions of roughness distributions of the noise KS equation in 1+1 dimensions show small finite-size effects.They are in good agreement with the Kardar-Parisi-Zhang(KPZ) equation's.

A cohesive zone model is employed in finite element formulation using nonlinear explicit dynamic algorithm.A 4-node tetrahedron element and a 6-node triangular prism element are chosen as volumetric and cohesive stress/displacement element,respectively.A bilinear constitutive equation is used to describe cohesive tractions and displacement jumps.Interfacial penetration of adjacent layers after complete rupture is avoided.A damage criterion is formulated in displacement jump space.The final displacement jump is calculated with Benzeggagh-Kenane's propagation criterion.The onset displacement jump is calculated with Turon's initial damage surface criterion.The code(CVFEM) can simulate material interface delamination under mixed-mode ratio loading in 3D.Three examples are shown.Numerical predictions are compared with those obtained by Abaqus 6.7.

1+1 dimensional Wolf-Villain model for molecular-beam epitaxy(MBE) growth is investigated with kinetic Monte-Carlo simulation in large scale and during long growth time so that crossover effects are eliminated.Global and local dynamic exponents are obtained.It is shown that Wolf-Villain model in 1+1 dimensions exhibits intrinsic anomalous scaling behavior in time and length simulated.The result is inconsistent with theoretical analysis by López.

With a sub-iterative technique for fluid dynamic equations and rigid-body dynamic equations,a coupling numerical method is proposed to explore the unsteady movement characteristics of aero-crafts and the effect of coupling time accuracy.It is shown that the motion finally becomes a self-maintained stable limit cycle oscillation.The amplitude with an increasing incidence angle shows a jump,which is quite close to the experimental result.The coupled numerical result with the second-order time accuracy depends hardly on the physical time step for this multi-system coupling.On the contrary,the uncoupled numerical result with one step time lag depends obviously on the physical time step selected.A longer time step results in unreal numerical results.

A pseudo-compressibility method developed by Rogers is used to solve the incompressible Navier-Stokes equation. Numerical flux is scattered through 3rd order Roe scheme and the 2nd order Harten-Yee TVD scheme separately. In order to accelerate convergence, several implicit methods(ADI-LU, LGS, LU-SGS) are accepted. Efficiency of different methods are shown as a classical flowfield around a cylinder in low Re(Re=200). Roe scheme is used to simulate two low speed unsteady problems:Low Re flowfield around a rotational cylinder(ω=1) and flowfield around a pitching NACA0015 airfoil with identical pitching rate.

Numerical simulations of the flow field around a double-wedge shaped projectile overtaking shocks, which move in two different directions, are carried out by solving unsteady compressible Navier-Stokes equations. In order to have enough grid resolution, the unified zonal fortified solution algorithm is used. Two test cases, the pursuing overtaking and the colliding overtaking are considered and discussed. The complex structure of wave systems and the aerodynamic forces are discussed. By comparing with the results acquired with the original methods, it is shown that the developed unified zonal method can be an effective and simple tool for handling complex bodies and enhancing the accuracy of numerical simulation.

The flowfields around a separating missile in supersonic free stream are studied numerically. Several typical flowfield structures in various separation distances are obtained. Two typical flow patterns are consistent very well with that observed in experiment. When the separation distance is small, the region between two stages is filled with "dead water" flow, the bottom drag of forebody is negative, the typical "afterbody effect" phenomenon occurs. When the separation distance is large, the complex interactive waves system is observed. After centain separation distance, the normal shock wave is formed in the front of the separated flow region before afterbody, hence the afterbody effect to forebody has been cut off.

The hypersonic flows around circular cylinders mounted flat plate are simulated by Reynolds-averaged Navier-Stokes equations and modified Baldwin-Lomax turbulence model. The zonal method and Roe third-order flux difference splitting scheme are used for the computation. The correspondent topological structures of flow patterns on plate surface are then obtained by topological theory. Some brief discussions are made with emphasizing on problems needed to be further studied.

Firstly, from the calculations of the heating rate on a blunt body in hypersonic flow and separation of shock/boundary layer interac tion flow, the capability of upwind TVD scheme for computing viscous flows is st udied. It is found that the computed heating rate and separated region are lower than the experimental data. The problem is the entropy correction formula. Then a new entropy correction formula is proposed, and the agreeable results compared with experiment are obtained. Secondly, using modified scheme, the study of control of separated flow over a smooth surface by body wall temperature is completed. The results show that the change of wall temperature can control the locati on of separation point and separation region effectively.

Three-dimension, compressible, internal flow solution obtained using a modifiedBeam-Warming implicit factorization scheme is presented. Steady-state solution is obtained by solving numerically the full Navier-Stokes equations from given initial conditions until the time-dependent terms become negligible. The configuration considered is a rectangular cross-section, S-shaped centreline diffuser duct with an exit/inlet area ratio of 2.25. TheMach number at the duct entrance is 0.9 with a Raynolds number of 5.82×10⁵. Two regions of separated flow exist within the diffuser. The detail flow field especially the developement process of secondary velocity patterns in transverse plane are pressented. Comparing with the results ofRef.[1]. they have a good agreement. The secondary velocity patterns are more reasonable.

The interaction between supersonic external flow and an exhaust jet forms a complex flowfield region near the missile afterbody. In this paper, the research about this interaction flows was completed with finite-difference method to solve N-S equations. The flowfield structures observed in experiment and it's relation with jet pressure ratio p_j/p_∞ were obtained. For freestream, M_∞=1.94, R_e∞=2.2×10⁵, for jet flow, M_j=3.0, three p_j/p_∞(1.03, 0.527 and 0.15) were selected. The numerical algorithm used is a modified Beam-Warming scheme. The nozzle base pressure coeficient and shock reflection length were compared with experimental data, good agreements were reached.

TVD scheme is one of the most advanced schemes for investigating supersonic and hypersonic complex flows in which shock wave is one of important properties up to date. In present paper, axisymmetric viscous flows about three indented nosetips and hypersonic flow about a blunt-cone body (θ=10°) at angles of attack were simulated with a two-order windward TVD scheme. High quatitive shocks and surface pressure distributions agreed with experiments and results from space-marching method were obtained. It is also demonstrated the unique advantages of present method for computing complex flows over re-entry vehicles.