Sentence examples for mean scalar gradient from inspiring English sources
Results obtained for the model problem of passive scalars evolving under the influence of a mean scalar gradient in homogeneous turbulence are found to be in reasonable agreement with experimental findings of Sirivat and Warhaft (1983).
The influence of differential diffusion on the scalar statistics is reduced by the presence of a constant mean scalar gradient and/or by the increase of the Reynolds number.
In Part I of this two-paper set, the model is studied analytically for homogeneous and mean scalar gradient flows without chemical reaction leading to an approach to set the model parameters that controls the unconditional scalar dissipation rate and delivers tunable localness.
Homogeneous turbulent flows are considered with and without the presence of constant mean scalar gradients, under both nonreacting and reacting nonpremixed conditions.
Simulation results for a three-stream problem, involving two inert scalars, and a multi-scalar test case with mean-scalar-gradients are presented.
Interestingly, the misfits of the scalar and vector measurements are similar, but the scalar gradient data have comparatively lower noise in polar regions than the scalar, the vector, and the vector gradient data.
This is confirmed by the time series of the E-W gradient residuals (observed gradient estimates minus their model predictions), presented in Fig. 3 for the scalar gradient and for the three vector gradient components, considering non-polar dark data.
As expected, the scatter of the scalar gradient residuals of (delta F_{text {EW, non-polar, dark}}) is smaller than that of the vector gradient.
The scalar gradient misfit is particularly low at mid-latitude, thus confirming the good quality of the measurements.
Mean scalar quantities on both sides of the premixed flame front are calculated in the same way.
The first is the solution of a generic scalar transport equation by advecting and diffusing the scalar gradient along a particle trajectory and onto a mesh, respectively, and recovering the scalar values using a Biot Savart-like summation.
