Numerical study of the effect of liquid sloshing inside TLD on suppression of gust wind-induced vibration in high rise buildings

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Needless to say that the use of TLD in damping of the light scale vibration in due to wind excitation as well as the large scale excitation on offshore platforms exhibits an effective dynamic absorber. One of the prime importance of using TLD as an effective absorber coupled with structure is to impart the effect of fatigue stresses accompanied with the repeated excitation loads. The serviceability of the high rise buildings and the steel towers is another important application of using TLD to suppress the building acceleration and realize the comfort and healthy conditions. The full scale measurements of the structure dynamic response exhibits an effective method for the validation of the structure design procedure and emphasize the accuracy of the numerical models suggested predicting the structure dynamic response. The current model behaves as a NSE model accurately predict the sloshing fluid motion inside TLD and handles the moving free surface by using the (VOF) method. The current model use the continuum surface force model CSF to model the discontinuity accompanied with wave breaking inside TLD. The numerical model used in this paper predicts the interaction between the structure dynamic response and highlights the damping effect of TLD groups allocated at different floors of tall buildings. The current model suggests a new criterion to detect the wave breaking and focus attention on the effect of wave breaking on the impact force in due to the sloshing fluid motion inside TLD for a wide range of excitation frequencies. The numerical model used in this paper handles the interaction between the structure dynamic response and the damping effect of TLD groups allocated at different floors of the tall building. The model was validated by a direct comparison with the full scale measurements of one of the high rise buildings. The direct comparison shows a good agreement proves that the current numerical model is a powerful tool used assess the damping effect of TLD on structure dynamic response.cf201

On wave breaking in tuned liquid dampers

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.Tuned Liquid Dampers (TLDs) are passive damping devices used to damp vibration due to wind in tall buildings and due to sea waves in offshore platforms. This paper pre-sents numerical results of wave breaking in TLDs obtained using a numerical model developed in-house. The model solves the full form of Navier-Stokes equations for viscous liquid sloshing and handles the moving free surface by using the volume of fluid method (VOF). Some of the previous numerical models invoke a two-phase flow model in con-junction with the VOF method to simulate the wave trans-formation and wave breaking in shallow water. However, these two-phase flow models give no account to the effect of body force on the free surface. The current model uses the continuum surface force model (CSF) which models the discontinuity accompanied with wave breaking as a con-tinuous transition where fluid properties such as density vary smoothly from one fluid to another. Numerous experi-mental studies reveal that the impulse pressure exerted on the tank walls varies in a similar nature as that of the applied excitation. Accordingly, the current numerical model sug-gests new formulae for the pressure at the left and right TLD walls. The present numerical results are in good agreement with experimental data. The current model is able to accu-rately detect surface wave breaking at various excitation frequencies.dc201

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)