38 research outputs found
Three-dimensional inelastic analysis for hot section components, BEST 3D code
The goal is the development of an alternative stress analysis tool, distinct from the finite element method, applicable to the engineering analysis of gas turbine engine structures. The boundary element method was selected for this development effort on the basis of its already demonstrated applicability to a variety of geometries and problem types characteristic of gas turbine engine components. Major features of the BEST3D computer program are described, and some of the significant developments carried out as part of the Inelastic Methods Contract are outlined
Development of an integrated BEM approach for hot fluid structure interaction
In the present work, the boundary element method (BEM) is chosen as the basic analysis tool, principally because the definition of temperature, flux, displacement and traction are very precise on a boundary-based discretization scheme. One fundamental difficulty is, of course, that a BEM formulation requires a considerable amount of analytical work, which is not needed in the other numerical methods. Progress made toward the development of a boundary element formulation for the study of hot fluid-structure interaction in Earth-to-Orbit engine hot section components is reported. The primary thrust of the program to date has been directed quite naturally toward the examination of fluid flow, since boundary element methods for fluids are at a much less developed state
Development of an integrated BEM approach for hot fluid structure interaction
Significant progress was made toward the goal of developing a general purpose boundary element method for hot fluid-structure interaction. For the solid phase, a boundary-only formulation was developed and implemented for uncoupled transient thermoelasticity in two dimensions. The elimination of volume discretization not only drastically reduces required modeling effort, but also permits unconstrained variation of the through-the-thickness temperature distribution. Meanwhile, for the fluids, fundamental solutions were derived for transient incompressible and compressible flow in the absence of the convective terms. Boundary element formulations were developed and described. For the incompressible case, the necessary kernal functions, under transient and steady-state conditions, were derived and fully implemented into a general purpose, multi-region boundary element code. Several examples were examined to study the suitability and convergence characteristics of the various algorithms
Development of an integrated BEM approach for hot fluid structure interaction
The development of a boundary element formulation for the study of hot fluid-structure interaction in earth-to-orbit engine hot section components is described. The initial primary thrust of the program to date was directed quite naturally toward the examination of fluid flow, since boundary element methods for fluids are at a much less developed state. This required the development of integral formulations for both the solid and fluid, and some preliminary infrastructural enhancements to a boundary element code to permit coupling of the fluid-structure problem. Boundary element formulations are implemented in two dimensions for both the solid and the fluid. The solid is modeled as an uncoupled thermoelastic medium under plane strain conditions, while several formulations are investigated for the fluid. For example, both vorticity and primitive variable approaches are implemented for viscous, incompressible flow, and a compressible version is developed. All of the above boundary element implementations are incorporated in a general purpose two-dimensional code. Thus, problems involving intricate geometry, multiple generic modeling regions, and arbitrary boundary conditions are all supported
Asymmetric Quantum Dialogue in Noisy Environment
A notion of asymmetric quantum dialogue (AQD) is introduced. Conventional
protocols of quantum dialogue are essentially symmetric as both the users
(Alice and Bob) can encode the same amount of classical information. In
contrast, the scheme for AQD introduced here provides different amount of
communication powers to Alice and Bob. The proposed scheme, offers an
architecture, where the entangled state and the encoding scheme to be shared
between Alice and Bob depends on the amount of classical information they want
to exchange with each other. The general structure for the AQD scheme has been
obtained using a group theoretic structure of the operators introduced in
(Shukla et al., Phys. Lett. A, 377 (2013) 518). The effect of different types
of noises (e.g., amplitude damping and phase damping noise) on the proposed
scheme is investigated, and it is shown that the proposed AQD is robust and
uses optimized amount of quantum resources.Comment: 11 pages, 2 figure
Lower bound of the expressibility of ansatzes for Variational Quantum Algorithms
The expressibility of an ansatz used in a variational quantum algorithm is
defined as the uniformity with which it can explore the space of unitary
matrices. The expressibility of a particular ansatz has a well-defined upper
bound. In this work, we show that the expressibiliity also has a well-defined
lower bound in the hypothesis space. We provide an analytical expression for
the lower bound of the covering number, which is directly related to
expressibility. We also perform numerical simulations to to support our claim.
To numerically calculate the bond length of a diatomic molecule, we take
hydrogen () as a prototype system and calculate the error in the energy
for the equilibrium energy point for different ansatzes. We study the variation
of energy error with circuit depths and show that in each ansatz template, a
plateau exists for a range of circuit depths, which we call the set of
acceptable points, and the corresponding expressibility is known as the best
expressive region. We report that the width of this best expressive region in
the hypothesis space is inversely proportional to the average error. Our
analysis reveals that alongside trainability, the lower bound of expressibility
also plays a crucial role in selecting variational quantum ansatzes
Controlled transportation of mesoscopic particles by enhanced spin orbit interaction of light in an optical trap
We study the effects of the spin orbit interaction (SOI) of light in an
optical trap and show that the propagation of the tightly focused trapping beam
in a stratified medium can lead to significantly enhanced SOI. For a plane
polarized incident beam the SOI manifests itself by giving rise to a strong
anisotropic linear diattenuation effect which produces polarization-dependent
off-axis high intensity side lobes near the focal plane of the trap. Single
micron-sized asymmetric particles can be trapped in the side lobes, and
transported over circular paths by a rotation of the plane of input
polarization. We demonstrate such controlled motion on single pea-pod shaped
single soft oxometalate (SOM) particles of dimension around m
over lengths up to 15 m . The observed effects are supported by
calculations of the intensity profiles based on a variation of the Debye-Wolf
approach. The enhanced SOI could thus be used as a generic means of
transporting mesoscopic asymmetric particles in an optical trap without the use
of complex optical beams or changing the alignment of the beam into the trap.Comment: 9 pages, 7 figure