In the near field of a subsonic jet, complex energy transport and transformation processes occur among kinetic, thermal, acoustic energies, which play crucial roles in jet instability noise radiation. Accurately characterizing features each component is essential for developing effective suppression technologies. Building upon Myers' [1991 J. Fluid Mech. 226 383] exact equation total disturbances arbitrary steady flow, present study develops modified based on hydro-acoustic mode...

A new family of compact vortex models is developed and taken as base vortical flows to numerically study the acoustic scattering by solving two-dimensional Euler equations in time domain with high-order accurate finite-difference methods nonreflecting boundary conditions. The computations scattered fields very small amplitude are found be excellent agreement a benchmark provided previous studies. Simulations for from Taylor reveal that strongly influenced two dimensionless quantities,...

Pr ‐doped Lu 3 Al 5 O 12 ( LuAG ) transparent ceramic, a potential scintillator material, was fabricated by sinter/hot isostatic pressing HIP ). The specimens were subjected to various post‐densification heat treatments and the evolution of porosity its relationship transparency monitored studied. Annealing necessary remove discoloration restore stoichiometry, but when performed at too high temperature it caused severe decrease in transparency. Transparency restored re ing, indicating that...

A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo is addressed. This paper mainly focuses two types possibly fast time-varying but bounded uncertainty within system: model parameter and uncertain nonlinearity. First, constructed as an nonlinear dynamic that can reflect practical mechanics transfer process system. Second, dynamical equation in form state space established by designing angular error. Third,...

Abstract Steam-assisted gravity drainage (SAGD) is an efficient thermal recovery technique for oil sands and extra heavy exploitation. The development of steam chamber goes through multi-stage physical processes SAGD production in a reservoir with interlayer. In this study, considering the situation that interlayer located directly above pair horizontal wells, we analyzed whole process development. We divided into stages I–V, which are first rising stage, lateral expansion second stage...

Digital 3D models represented by triangular meshes are now broadly available and they becoming a new multimedia data type after sound, images video. For many applications there is need to convert such mesh into spline surfaces. This paper describes an adaptive algorithm that automatically converts T-spline surface based on optimization techniques. The key issues of the include parameterization input points, determination topology surface, calculation least squares control points. Some...

The steam chamber rising process is an essential feature of steam-assisted gravity drainage. development a and its production capabilities have been the focus various studies. In this paper, new analytical model proposed that mimics predicts oil rate during stage. was assumed to circular geometry relative plane. includes determining relation between capability. daily production, ratio, height curves influenced by different parameters were drawn. addition, curve sensitivities thoroughly...

When acoustic waves propagate through a volume of vortical flows, the strong nonlinear scattering lead amplitude, frequency, and phase incident to change obviously. As one most significant problems in area aeroacoustics, by flow plays main role industrial applications scientific research. In this study, we start from an elementary vortex model. The plane Taylor is investigated solving two-dimensional Euler equations numerically time domain. To resolve small-amplitude waves,...

The spatial structure and time evolution of tornado-like vortices in a three-dimensional cavity are studied by topological analysis numerical simulation. topology theory the unsteady vortex rectangular coordinate system (Zhang, Zhang & Shu, J. Fluid Mech. , vol. 639, 2009, pp. 343–372) is generalized to curvilinear system. Two functions $\lambda (q_1,t)$ $q(q_1,t)$ obtained determine sectional streamline pattern cross-section perpendicular axis meridional plane, respectively. spiral...

A hydrodynamic and acoustic mode decomposition method for velocity pressure based on Helmholtz momentum equation is proposed. It able to decompose the flow variables of into their vortical, acoustic, entropic components. The verified validated by a Mach 0.9 turbulent jet flow. spectral properties decomposed components verify that successfully separates two parts. Spectral proper orthogonal analysis fields clearly identifies spatial structures first three radial orders trapped waves in...

The scattering of acoustic waves by a vortex is fundamental problem the propagation in complex flow field, which plays an important role academic research and engineering application for sound source localization, target recognition detection, far field noise prediction, such as aircraft wake identification, detection ranging, forecasting turbulent shear flow, measurement localization wind tunnel test, etc. nonlinear phenomenon occurs when wave passes through vortex, mainly related to...

Lutetium oxyorthosilicate (Lu₂SiO₅:Ce³⁺, commonly known as LSO) is a scintillator of choice for medical imaging applications such Positron Emission Tomography (PET) because its high light output, gamma ray stopping power and fast response. In the current study, phase-pure LSO ceramics were obtained with degree optical transparency excellent scintillation properties. These prepared by combining nanotechnology sinter-HIP approach. We found that densities...

Abstract The development of high‐performance ultra‐high molecular weight polyethylene (UHMWPE) fiber laminate is great significance in the field bulletproof materials. However, due to poor heat resistance UHMWPE fibers, it challenging achieve exceptional mechanical properties laminates prepared via hot‐pressing. In this study, we employ a self‐made ultraviolet (UV) cross‐linked fully drawn yarn (UVFDY), which exhibits excellent resistance, prepare UVFDY/unsaturated polyester resin (UPR)...

This paper considers the problem of parameterizing triangular meshes that have tubular shapes. Unlike an open mesh is plane topological type, a gives rise to some special issues in parameterization due its structure. In this paper, we present edge based method, which edges rather than vertices are treated as target for parameterization. It improves cutting-based algorithms cut make it disk topologically. The cutting paths their zigzag shape leads suboptimal parameterizations and finding good...

On the degradation of electrical performance due to main reflector deformation large shaped Cassegrain antennas, a method for compensation by moving subreflector is presented. A group best-fit paraboloids are found least-square fitting theoretical discrete data. The used fit deformed reflector, with constraint all these focuses being in line. parameters optimized and adjustments derived ratio subreflector. at various attitudes saved look-up table real-time compensate deformation. From...