In this paper, an extremely fast technique is introduced to evaluate the shielding effectiveness of a rectangular enclosure of finite wall thickness and numerous square or circular small apertures subject to a normally incident plane wave. The technique is based on the traditional waveguide circuit model where the enclosure is replaced with an equivalent shorted transmission line. In the propos...

Both animals and human toddlers can find an object in a rectangular enclosure after they have been disoriented. They use geometric cues (relative lengths of walls) to discriminate among different corners (e.g. long wall to the left, short to the right). It has been claimed that this ability is 'modular', i.e. exclusively geometric. The present study demonstrates that the ability toddlers exhibi...

This paper explores acoustical (or time-dependent) radiosity--a geometrical-acoustics sound-field prediction method that assumes diffuse surface reflection. The literature of acoustical radiosity is briefly reviewed and the advantages and disadvantages of the method are discussed. A discrete form of the integral equation that results from meshing the enclosure boundaries into patches is present...

Model equations describing large scale buoyant convection in an enclosure are formulated with the vorticity and stream function as dependent variables. The mathematical model, based on earlier work of the authors, is unique in two respects. First, it neglects viscous and thermal conductivity effects. Second the fluid is taken to be thermally expandable: large density variations are allowed whil...

Passive heat transfer from enclosures with rectangular fins is studied both experimentally and theoretically. Several sample enclosures with various lengths are prepared and tested. To calibrate the thermal measurements and the analyses, enclosures without fins (“bare” enclosures) are also prepared and tested. Surface temperature distribution is determined for various enclosure lengths and heat...

The present study focused on the investigation of the effects of roughness elements on heat transfer during natural convection in a rectangular cavity using numerical technique. Roughness elements were introduced on the bottom hot wall with a normalized amplitude (A*/H) of 0.1. Thermal and hydrodynamic behaviors were studied using computational method based on Lattice Boltzmann method (LBM). Nu...