Statistics of surface renewal of passive scalars in free-surface turbulence

Statistics and geometry of passive scalars in turbulence

We present direct numerical simulations of the mixing of the passive scalar at modest Taylor microscale 10 R 42 and Schmidt numbers larger than unity 2 Sc 32 . The simulations resolve below the Batchelor scale up to a factor of 4. The advecting turbulence is homogeneous and isotropic, and is maintained stationary by stochastic forcing at low wave numbers. The passive scalar is rendered stationa...

Passive Scalars in Stratified Turbulence

The statistics of a passive scalar in randomly forced and strongly stratified turbulence is investigated by numerical simulations including a horizontal passive scalar mean gradient. We observe that horizontal isotropy of the passive scalar spectrum is satisfied in the inertial range. The spectrum has the form Eθ(kh) = Cθεθε −1/3 K k −5/3 h , where εθ, εK are the dissipation of scalar variance ...

the study of bright and surface discrete cavity solitons dynamics in saturable nonlinear media

امروزه سالیتون ها بعنوان امواج جایگزیده ای که تحت شرایط خاص بدون تغییر شکل در محیط منتشر می-شوند، زمینه مطالعات گسترده ای در حوزه اپتیک غیرخطی هستند. در این راستا توجه به پدیده پراش گسسته، که بعنوان عامل پهن شدگی باریکه نوری در آرایه ای از موجبرهای جفت شده، ظاهر می گردد، ضروری است، زیرا سالیتون های گسسته از خنثی شدن پراش گسسته در این سیستم ها بوسیله عوامل غیرخطی بوجود می آیند. گسستگی سیستم عامل...

Experiments on Free-Surface Turbulence

Effective diffusivity of passive scalars in rotating turbulence.

We use direct numerical simulations to compute turbulent transport coefficients for passive scalars in turbulent rotating flows. Effective diffusion coefficients in the directions parallel and perpendicular to the rotation axis are obtained by studying the diffusion of an imposed initial profile for the passive scalar, and calculated by measuring the scalar average concentration and average spa...