Browsing by Author "Lopes, A."
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- Evaluation of errors on the CFD computation of air flow and heat transfer around the human bodyPublication . Martinho, Nuno; Lopes, A.; Gameiro da Silva, M.A detailed computer aided design model representing a female human body was created from a 3-D scan of a full scale thermal manikin. The sensible heat losses due to convection and radiation for a person seated in a rectangular room were calculated using CFD simulations, as well as the parameters characterizing the flow around the body including air velocity and temperature. The accuracy of numerical results was evaluated in terms of the physical approximation errors, namely inlet boundary conditions and turbulence models, and spatial discretization errors due to the number of grid elements and grid refinement near solid surfaces. Results were compared to published data from two tests performed in conditions that portrayed the CFD simulations. The use of: a mixed turbulence model between k-e{open}, for zones away from solid surfaces, and k-ω, for zones close to solid surfaces; values of the dimensionless y + parameter inferior to 5 jointly with a low-Reynolds method to model the flow in the near-wall region of the human surface and inlet non-uniform boundary profiles for temperature, velocity and turbulence intensity, leaded to good agreement with experimental results, with a global mean relative error of the order of 7%, with a standard deviation of 4%, in terms of convective and radiative heat flux between the human body and the thermal environment.
- North African dust intrusions and increased risk of respiratory diseases in Southern PortugalPublication . Silva, T.; Fragoso, M.; Almendra, R.; Vasconcelos, J.; Lopes, A.; Faleh, A.The study of dust intrusions in Portugal is still a subject on which little investigation has been made, especially in terms of their effects. Thus, this work aims to achieve two goals: firstly, to characterize the dust intrusions in the study area; and secondly, to evaluate the possible statistical association between the dust intrusion days and hospital admissions due to respiratory diseases. Dust intrusions in Portugal are prevalent during the summer season. During this season, the dust plumes tend to cover broader areas than in the other seasons and they have origin in the North African countries. In the study area for the period between 2005 and 2015, the relative risk of urgent hospitalizations due to respiratory diseases was 12.6% higher during dust intrusion days. In order to obtain this statistical association, a Distributed Lag Nonlinear Model was developed. With this work, we expect to help the development of further studies regarding North African dust intrusions in Portugal, more precisely their effects on human health.