The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform

Ahmet Kahraman - One of the best experts on this subject based on the ideXlab platform.

  • On the response of a preloaded mechanical oscillator with a clearance: Period-doubling and chaos
    Nonlinear Dynamics, 1992
    Co-Authors: Ahmet Kahraman
    Abstract:

    The dynamic behavior of a harmonically excited, preloaded mechanical oscillator with dead-zone nonlinearity is described quantiatively. The governing strongly nonlinear differential equation is solved numerically. Damping coefficient-force ratio maps for two different values of the excitation frequency have been formed and the boundaries of the regions of different motion types are determined. The results have been compared with the results of the forced Duffing's equation available in the literature in order to identify the differences between cubic and dead-zone nonlinearities. Period-doubling bifurcations, which take place with a change of any of the system parameters, have been found to be the most common route to chaos. Such bifurcations follow the scaling rule of Feigenbaum. b half length of the clearance. c viscous damping coefficient. f nonlinear displacement function. % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4baFfea0dXde9vqpa0lb9% cq0dXdb9IqFHe9FjuP0-iq0dXdbba9pe0lb9hs0dXda91qaq-xfr-x% fj-hmeGabiqaaiaacaGaaeqabaWaaeaaeaaakeaaceqGgbGbaKaaaa% a!3332!\[{\rm{\hat F}}\] alternating force to mean force ratio. F_aalternating force amplitude. F_mmean force (preload). j period-doubling index. k stiffness coefficient. m mass. n period number. t dimensionless time. x dimensionless displacement. α variable system parameter in period-doubling bifurcation. δ Feigenbaum number. λ a point on the ζ-% MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4baFfea0dXde9vqpa0lb9% cq0dXdb9IqFHe9FjuP0-iq0dXdbba9pe0lb9hs0dXda91qaq-xfr-x% fj-hmeGabiqaaiaacaGaaeqabaWaaeaaeaaakeaaceqGgbGbaKaaaa% a!3332!\[{\rm{\hat F}}\] map. ω dimensionless excitation frequency. ω _nnatural frequency of the corresponding linear system. ζ damping ratio. Superscripts : (−) Dimensional Quantity. (.) differentiation with respect to t .

Jacqueline H. Chen - One of the best experts on this subject based on the ideXlab platform.

  • Estimates of the three-Dimensional flame surface density and every term in its transport equation from two-Dimensional measurements
    Proceedings of the Combustion Institute, 2011
    Co-Authors: Evatt R. Hawkes, Ramanan Sankaran, Jacqueline H. Chen
    Abstract:

    Abstract The flame surface density approach is one of the most established techniques for the modelling of turbulent premixed combustion. There has been considerable interest in the experimental measurement of the flame surface density and quantities involved in its transport equation, namely: strain, curvature, and displacement speed. Because of the difficulty involved in performing three-Dimensional measurements, the vast majority of this work has been performed in two spatial dimensions. Therefore an assumption is required to relate the two-Dimensional measurement to the three-Dimensional reality. In the present article, new relationships are derived to relate the statistical mean values of measured two-Dimensional quantities to those of the true three-Dimensional Quantity in the case of isotropic scalar fields and turbulence. The relationships are derived for the flame surface density as well as for every term in its transport equation. To assess the performance of the relationships, direct numerical simulations of turbulent, premixed, methane–air slot-jet flames are employed. In all cases considered, the agreement is very good away from a small region near the simulated burner exit. The agreement improves with downstream distance and with Reynolds number.

Brian D. Knox - One of the best experts on this subject based on the ideXlab platform.

Y. M. Tsai - One of the best experts on this subject based on the ideXlab platform.

  • THERMOELASTIC PROBLEM OF UNIFORM HEAT FLOW DISTURBED BY A FLAT TOROIDAL CRACK IN A TRANSVERSELY ISOTROPIC MEDIUM
    Journal of Thermal Stresses, 2000
    Co-Authors: Y. M. Tsai
    Abstract:

    The thermoelastic problem of uniform heat flow disturbed by a flat toroidal crack in a transversely isotropic medium is investigated using the method of Hankel transforms. The three-part mixed thermoelastic boundary conditions are satisfied using the tech niques of triple integral equations and multiplying factors. The stress intensity factors at the inner and outer crack tips are obtained in exact expressions as the products of a Dimensional Quantity and nonDimensional functions. The fracture transition of a flat toroidal crack to a penny-shaped crack and to a two-Dimensional line crack is studied at different values of the ratio of the inner crack radius to the outer crack radius.

  • Thermoelastic behavior of a transversely isotropic material containing a flat toroidal crack
    Journal of Thermal Stresses, 1998
    Co-Authors: Y. M. Tsai
    Abstract:

    The thermoelastic behavior of a transversely isotropic material containing a flat toroidal crack is investigated using the techniques of Hankel transforms and multiplying factors. The thermal conditions are symmetrical with respect to the crack plane and the boundary conditions have three different parts. Exact expressions for the thermoelastic stress intensity factors at the inner and outer crack tips are obtained as the products of a Dimensional Quantity and nonDimensional functions. The fracture transition of a flat toroidal crack to a penny-shaped crack and to a central crack is studied at different values of the ratio of the inner crack radius to the outer crack radius. The temperature distribution on the crack plane is also presented at different values of inner and outer crack radii

D Schertzer - One of the best experts on this subject based on the ideXlab platform.

  • 23/9 Dimensional anisotropic scaling of passive admixtures using lidar data of aerosols
    Physical Review E : Statistical Nonlinear and Soft Matter Physics, 2004
    Co-Authors: M. Lilley, S. Lovejoy, K Strawbridge, D Schertzer
    Abstract:

    In buoyancy-driven flows, another Dimensional Quantity appears in addition to the energy flux. Classically, this leads to the prediction that at large scales, isotropic Bolgiano-Obukhov (BO) scaling can dominate isotropic Kolmogorov scaling. We investigate this in the atmosphere by using state-of-the-art high-powered lidar data. We examine simultaneous horizontal and vertical sections of passive scalar surrogates over the ranges 100 m to 120 km and 3 m to 4.5 km, respectively. Overall, this spans the crucial ""mesoscale"" and involves nearly 1000 times more data than the largest relevant experiments to date. Rather than a transition from one isotropic regime to another, we find that the two regimes always coexist in an anisotropic Corrsin-Obukhov law with the Kolmogorov holding in the horizontal, and the BO holding in the vertical. The stratification is quantified by an elliptical dimension D(el) found to be equal to 2.55+/-0.02. This anisotropic scaling is very close to that predicted by the 23/9 Dimensional unified scaling model of the atmosphere and is consistent with observations of the horizontal wind.