Natural convection in a square cavity with uniformly heated and/or insulated walls using marker-and-cell method

In this study, a numerical investigation has been performed using the computational Harlow-Welch MAC (Marker and Cell) finite difference method to analyse the unsteady state two-dimensional natural convection in lid-driven square cavity with left wall maintained at constant heat flux and remaining walls kept thermally insulated. The significant parameters in the present study are Reynolds number (Re), thermal Grashof number (Gr) and Prandtl number (Pr) and Peclét number (Pe =PrRe). The structure of thermal convection patterns is analysed via streamline, vorticity, pressure and temperature contour plots. The influence of the thermophysical parameters on these distributions is described in detail. Validation of solutions with earlier studies is included. Mesh independence is also conducted. It is observed that an increase in Prandtl number intensifies the primary circulation whereas it reduces the heat transfer rate. Increasing thermal Grashof number also decreases heat transfer rates. Furthermore the isotherms are significantly compressed towards the left (constant flux) wall with a variation in Grashof number while Peclét number is fixed. The study is relevant to solar collector heat transfer simulations and also crystal growth technologies

REPRODUCIBILITY OF GROUP EVACUATION BEHAVIOR OF THE ELDERLY BY SUBJECTS WEARING ELDERLY SIMULATOR

ABSTRACT Because a rapid aging of society is being realized, evacuation planning that considers the inclusion of aged people is becoming very important. For the introduction of the design guide for evacuation from barrier-free buildings, experiments have been widely conducted using an ordinary person wearing an "elderly simulator", which is called "Instant Senior", mostly for safety reasons. However, the reproducibility of the evacuation behavior of elderly people has not yet been established, therefore the behavior of groups with ordinary people along with Instant Seniors are compared with those of ordinary people with Actual Seniors in order to study the suitability of using Instant Seniors instead of Actual Seniors. From the results, we concluded that Instant Seniors are appropriate as subjects for modeling the walking behavior of a group evacuation, from the point that they become obstacles to ordinary people as Actual Seniors actually do. Attention to the method of using Instant Seniors to improve reproducibility is also discussed