In this study, the thermal characteristics of turbulent nanofluid flow in a helical tube in the tube heat exchanger (HTTHE) were assessed numerically through computational fluid dynamics (CFD) simulation. The findings of both the turbulent models: realizable k-epsion (k-ε) and re-normalisation group (RNG) k-epsilon were compared. The temperature distribution contours show that realizable and RN...

turbulent mixed convection of a nanofluid (water/al2o3, φ=.02) has been studied numerically. two-phase mixture model has been used to investigate the effects of nanoparticles mean diameter on the flow parameters. nanoparticles distribution at the tube cross section shows that the particles are uniformly dispersed. the non-uniformity of the particles distribution occurs in the case of large nano...

Hydrodynamic of a turbulent impinging jet on a flat plate has been studied experimentally and numerically. Experiments were conducted for the Reynolds number range of 72000 to 102000 and a fixed jet-to-plate dimensionless distance of H/d=3.5. Based on the experimental setup, a multi-phase numerical model was simulated to predict flow properties of impinging jets using two turbulent models. Mesh...

mixed convection is a fundamentally significant heat transfer mechanism that occurs in selection industrial and technological applications. in this study, first the laminar mixed convection inside rectangular enclosure with moving wall and aspect ratio=10 is modeled and then the results are compared with other investigate. after showing varity of results, the investigation is continued with tur...

In this paper, an enhancement design of communication system using optical radio frequency (RF) waves in free space optical communication (FSO) system is presented. To our knowledge, it is the first time that the effect of Gamma-Gamma turbulent channel model on the performance of the proposed system is analyzed and simulated. To obtain an optical communication system with good performance and h...

The present article is a survey research that intends to explore the social factors affecting social identity. Statistical population consisted of over 551653 youth aged 15-29 living in the city of Esfahan. From among them, 384 persons were selected as sample of the study based on sampling formula using quota sampling method. Research hypotheses were formulated by referring to the theories give...

Turbulent social environments are associated with health and developmental risk, yet mechanisms have been understudied. Guided by a life course framework and stress theory, this study examined the association between turbulent life transitions (including frequent residential mobility, school transitions, family structure disruptions, and homelessness) and exposure to violence during adolescence...

one of the popular and well known models in boundary layer that is implemented in most of the operational and familiar models is the mellor-yamada model of atmospheric boundary layer. one reason that this model is so popular is its ability in simulations and exposing of different phenomena in the boundary layer. this model has been constructed based on second order closure hypothesis. beside al...