Search

The World Health Organization has pointed out that airborne transmission via aerosol particles can be a strong vector for the spread of SARS-CoV-2. Protecting occupants from infectious diseases or harmful particulate matter (PM) in general can be challenging. While experimentally outlining the detailed flow of PM in rooms may require complex setups, computational fluid dynamics (CFD) simulations can provide insights into improving the safety of the built environment and the most effective positioning of air-purifying devices. While previous studies have typically leveraged Reynolds-averaged Navier–Stokes (RANS) approaches for predicting particle propagation, the turbulence length scales accurately captured in these simulations may not be sufficient to provide a realistic spread and the mixing of particles under the effects of forced convection. In this paper, we experimentally validate a Lattice Boltzmann very large eddy simulation (VLES) approach including particle modeling. We also demonstrate how this simulation approach can be used to improve the effectiveness of air filtration devices in realistic office environments. [ABSTRACT FROM AUTHOR]

When investigating combustion instabilities using analytical models, it has previously been assumed that the compact flame assumption implied that the flame-front movement did not need to be taken into account to solve the acoustics. This article shows that this is not necessarily the case. This article presents a generalization of such models of anchored V-flames to allow the flame “source” of acoustic waves to vary its position in time so as to track the flame-front location. A method for solving this problem is then presented. It is found that accounting for the flame front movement can alter both the linear stability of the combustor, and (for cases that remain unstable) the limit cycle amplitude. Significant changes in limit cycle amplitude are observed across a large range of operating conditions. The flame front movement has so far only been seen to provide a stabilizing effect, reducing the Rayleigh source term. Self-tuning regulator adaptive control methods appear to be unaffected by accounting for the moving flame front. [ABSTRACT FROM AUTHOR]

This paper deals with the ways in which young Israeli lesbians use their bodies in order to detach themselves from both straight women and the older generation of lesbians. They make use of bodily cultural codes borrowed from the mainstream youth culture, yet modified in articulation with the lesbian subculture. The manipulation of codes brings forward the complexity of their age/gender/sexual identity as dictated by the postmodern era. The study is based on in-depth interviews with lesbians who live in an urban environment. Results indicate that young lesbians use two complementary codes. On the one hand they apply bodily codes in accordance with youth culture. Simultaneously, they assign different meanings to items culturally associated with traditional heterosexual women's sexuality. They claim the older generation to neglect physical attractiveness, out of feminist ideology; they insist that nowadays a woman can be both sexy and lesbian. Thus, mingling with heterosexual youngsters is made possible while claiming their sex-appeal is not meant to attract men. [ABSTRACT FROM AUTHOR]