We consider transport of a passive scalar by an isotropic turbulent velocity field in the presence of a mean scalar gradient. The velocity–scalar cospectrum measures the distribution of the mean scalar flux across scales. An inequality is shown to bound the magnitude of the cospectrum in terms of the shell-summed energy and scalar spectra. At high Schmidt number, this bound limits the possible ...

We study the statistical properties of volatility—a measure of how much the market is likely to fluctuate. We estimate the volatility by the local average of the absolute price changes. We analyze (a) the S&P 500 stock index for the 13-year period Jan 1984 to Dec 1996 and (b) the market capitalizations of the largest 500 companies registered in the Trades and Quotes data base, documenting all t...

We report on the detection of PSR 1706-44 in two ROSAT-PSPC observations. The recorded source counts are unpulsed with a 2 pulsed fraction upper limit of 18%. Spectral analysis did not distinguish between black-body and power law models; however, we argue that the lack of pulsations and the similarity in the pulsar's spin parameters to those of the Vela pulsar favour a power law model dN=dE / E...

A numerical investigation is performed for non Newtonian fluids flow between two concentric cylinders. The D2Q9 lattice Boltzmann model developed from the Bhatangar-Gross-Krook (LBGK) approximation is used to obtain the flow field for fluids obeying to the power-law model. The inner and outer cylinders rotate in the same and the opposite direction while the end walls are maintained at rest. The...

in this paper, the influence of the constituent volume fractions by changing the values of the power-law exponent with uniform pressure on the vibration frequencies of reinforced functionally graded cylindrical shells is studied. the fgm shell with ring is developed in accordance to the volume fraction law from two constituents namely stainless steel and nickel. these constituents are graded th...

rheological characteristics of al2o3, cuo and tio2 nano particles were investigated in oil asthe base fluid at 1 and 2 wt.%. constitutive relations for non-newtonian fluid were discussedbased on the power-law model. measured viscosities of each nanofluid were used to evaluatethe power-law and consistency index. results indicated that the nanofluid viscosity decreasedby increasing the concentrat...

in this work the effect of the accuracy of a fae detonation modeling on the generated blast wave is investigated. first, a one-dimensional numerical simulation with a reduced chemical kinetics of c2h2-o2-ar, involving 25 elementary reactions, is used as the base model. the properties of the blast calculated with this model is compared with those of simpler models, the similarity solution of tay...