Lattice Boltzmann simulation of natural convection in an L-shaped enclosure in the presence of nanofluid

Abstract

Traffic accidents in the streets have become a very serious issue in Japan. In order to reduce the traffic accidents in the streets, a proper speed reduction of the vehicle is important. Although there are many approaches to make the vehicles reduce the speed, this study focuses on a user measures to encourage the speed reduction by providing the information. Recent years, there was a traffic calming study in which some people stand the roadside and then remind the drivers to decrease their driving speeds by showing the vehicle's speed. In this study, by referring the existed study, we tried to grasp the measurement issues from the viewpoint of vehicle behavior such as reduction of the speed, evaluation by the drivers and neighborhoods consciousness, and possibility of the supports by the government in this area. Results obtained in this study are as follows. 1) When provided speed information for the over speed limit vehicles, it was found that the speed is reduced markedly near the provision position. 2) Vehicle speed provision activities were accepted favorably to the driver. In addition, the trend was noticeable to the driver who lives in the vicinity of the activities. 3) It was recognized by neighborhoods that vehicle speed provision activities are effective compared to the traffic safety campaign activity as usual. In addition, the tendency was more remarkable in the people who recognized that the vehicle speed in the street was fast. 4) The problems listed by the road administrators for the spread of vehicle speed information provision activities were the relations with other policies, the generalization of the effects, and consideration for the trouble evasion.

LBM Analysis of Micro-Convection in MHD Nanofluid Flow

“…Flow behaviours and the average rate of heat transfer in terms of the Nu as well as the thermal conductivity of nanofluid is effectively changed with the particle volume fraction and particle diameter with a fixed Ra [39]. The mean Nu increased with increase in Ra [40]. The flow and heat transfer characteristics of Al 2 O 3 -water nanofluid in the square cavity are more sensitive to viscosity than to thermal conductivity [41].…”

Lattice Boltzmann Simulation of Magnethydrodynamics Natural Convection in an L-Shaped Enclosure

“…The presented results show that fluid flow and heat transfer characteristics are highly affected by the nanoparticles Brownian motion. In addition, the heat generation or absorption influences the heat transfer in the cavity at Ra = 10 3 more than other Raleigh numbers as the least effect is observed at Ra = 10 6 .…”

“…Mliki et al [6] analyzed the natural convection heat transfer in an L-shaped cavity filled with nanofluids, by using lattice Boltzmann method. They analyzed the effect of different parameters such as Rayleigh number (10 3 ≤ Ra ≤ 10 6 ), aspect ratio of the L-shaped enclosure (0.2≤AR≤0.6) and nanoparticle volume concentration (0.0≤ ≤0.05) on the flow and temperature fields.…”

“…Also it was found that the average Nusselt number decreases by an increase in Hartmann number, especially for higher Rayleigh numbers. Mliki et al [8] studied the Cu/water nanofluid double-diffusive natural convection in a C-shaped cavity. They showed that heat and mass transfers decrease with increasing the Hartmann number.…”

“…Chen and Cheng [9] applied the finitevolume method and curvilinear coordinates to investigate buoyancy driven heat transfer enhancement in an inclined arcshaped enclosure. They reported that the arc-shaped enclosure for Pr=4.0 at Gr= 4×10 6 and θ= π/2 exhibits the best heat transfer performance. Also it was found that the increase in natural convection heat transfer becomes appreciable when Gr>10 5 .…”