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  1. Article: The computational fluid dynamics-based epidemic model and the pandemic scenarios.

    Dbouk, Talib / Drikakis, Dimitris

    Physics of fluids (Woodbury, N.Y. : 1994)

    2022  Volume 34, Issue 2, Page(s) 27104

    Abstract: This study presents a computational fluid dynamics, susceptible-infected-recovered-based epidemic model that relates weather conditions to airborne virus transmission dynamics. The model considers the relationship between weather seasonality, airborne ... ...

    Abstract This study presents a computational fluid dynamics, susceptible-infected-recovered-based epidemic model that relates weather conditions to airborne virus transmission dynamics. The model considers the relationship between weather seasonality, airborne virus transmission, and pandemic outbreaks. We examine multiple scenarios of the COVID-19 fifth wave in London, United Kingdom, showing the potential peak and the period occurring. The study also shows the importance of fluid dynamics and computational modeling in developing more advanced epidemiological models in the future.
    Language English
    Publishing date 2022-02-02
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472743-2
    ISSN 1089-7666 ; 1070-6631
    ISSN (online) 1089-7666
    ISSN 1070-6631
    DOI 10.1063/5.0082090
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: On pollen and airborne virus transmission.

    Dbouk, Talib / Drikakis, Dimitris

    Physics of fluids (Woodbury, N.Y. : 1994)

    2021  Volume 33, Issue 6, Page(s) 63313

    Abstract: This study investigates how airborne pollen pellets (or grains) can cause severe respiratory-related problems in humans. Given that pollen pellets can capture ribonucleic acid viruses, we show that airborne pollen grains could transport airborne virus ... ...

    Abstract This study investigates how airborne pollen pellets (or grains) can cause severe respiratory-related problems in humans. Given that pollen pellets can capture ribonucleic acid viruses, we show that airborne pollen grains could transport airborne virus particles such as the airborne coronavirus (CoV) disease (COVID-19) or others. We consider the environmental conditions featuring the highest pollen concentration season and conduct computational multiphysics, multiscale modeling and simulations. The investigation concerns a prototype problem comprising the transport of 10
    Language English
    Publishing date 2021-06-22
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472743-2
    ISSN 1089-7666 ; 1070-6631
    ISSN (online) 1089-7666
    ISSN 1070-6631
    DOI 10.1063/5.0055845
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: On airborne virus transmission in elevators and confined spaces.

    Dbouk, Talib / Drikakis, Dimitris

    Physics of fluids (Woodbury, N.Y. : 1994)

    2021  Volume 33, Issue 1, Page(s) 11905

    Abstract: The impact of air ventilation systems on airborne virus transmission (AVT), and aerosols in general, in confined spaces is not yet understood. The recent pandemic has made it crucial to understand the limitations of ventilation systems regarding AVT. We ... ...

    Abstract The impact of air ventilation systems on airborne virus transmission (AVT), and aerosols in general, in confined spaces is not yet understood. The recent pandemic has made it crucial to understand the limitations of ventilation systems regarding AVT. We consider an elevator as a prototypical example of a confined space and show how ventilation designs alone, regardless of cooling or heating, contribute to AVT. Air circulation effects are investigated through multiphase computational fluid dynamics, and the performance of an air purifier in an elevator for reducing AVT is assessed. We have investigated three different flow scenarios regarding the position and operation of inlets and outlets in the elevator and a fourth scenario that includes the operation of the air purifier. The position of the inlets and outlets significantly influences the flow circulation and droplet dispersion. An air purifier does not eliminate airborne transmission. The droplet dispersion is reduced when a pair of an inlet and an outlet is implemented. The overall practical conclusion is that the placement and design of the air purifier and ventilation systems significantly affect the droplet dispersion and AVT. Thus, engineering designs of such systems must take into account the flow dynamics in the confined space the systems will be installed.
    Language English
    Publishing date 2021-01-26
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472743-2
    ISSN 1089-7666 ; 1070-6631
    ISSN (online) 1089-7666
    ISSN 1070-6631
    DOI 10.1063/5.0038180
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Correcting pandemic data analysis through environmental fluid dynamics.

    Dbouk, Talib / Drikakis, Dimitris

    Physics of fluids (Woodbury, N.Y. : 1994)

    2021  Volume 33, Issue 6, Page(s) 67116

    Abstract: It is well established that the data reported for the daily number of infected cases during the first wave of the COVID-19 pandemic were inaccurate, primarily due to insufficient tracing across the populations. Due to the uncertainty of the first wave ... ...

    Abstract It is well established that the data reported for the daily number of infected cases during the first wave of the COVID-19 pandemic were inaccurate, primarily due to insufficient tracing across the populations. Due to the uncertainty of the first wave data mixed with the second wave data, the general conclusions drawn could be misleading. We present an uncertainty quantification model for the infected cases of the pandemic's first wave based on fluid dynamics simulations of the weather effects. The model is physics-based and can rectify a first wave data's inadequacy from a second wave data's adequacy in a pandemic curve. The proposed approach combines environmental seasonality-driven virus transmission rate with pandemic multiwave phenomena to improve statistical predictions' data accuracy. For illustration purposes, we apply the new physics-based model to New York City data.
    Language English
    Publishing date 2021-06-22
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472743-2
    ISSN 1089-7666 ; 1070-6631
    ISSN (online) 1089-7666
    ISSN 1070-6631
    DOI 10.1063/5.0055299
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Fluid dynamics and epidemiology: Seasonality and transmission dynamics.

    Dbouk, Talib / Drikakis, Dimitris

    Physics of fluids (Woodbury, N.Y. : 1994)

    2021  Volume 33, Issue 2, Page(s) 21901

    Abstract: Epidemic models do not account for the effects of climate conditions on the transmission dynamics of viruses. This study presents the vital relationship between weather seasonality, airborne virus transmission, and pandemic outbreaks over a whole year. ... ...

    Abstract Epidemic models do not account for the effects of climate conditions on the transmission dynamics of viruses. This study presents the vital relationship between weather seasonality, airborne virus transmission, and pandemic outbreaks over a whole year. Using the data obtained from high-fidelity multi-phase, fluid dynamics simulations, we calculate the concentration rate of Coronavirus particles in contaminated saliva droplets and use it to derive a new Airborne Infection Rate (AIR) index. Combining the simplest form of an epidemiological model, the susceptible-infected-recovered, and the AIR index, we show through data evidence how weather seasonality induces two outbreaks per year, as it is observed with the COVID-19 pandemic worldwide. We present the results for the number of cases and transmission rates for three cities, New York, Paris, and Rio de Janeiro. The results suggest that two pandemic outbreaks per year are inevitable because they are directly linked to what we call weather seasonality. The pandemic outbreaks are associated with changes in temperature, relative humidity, and wind speed independently of the particular season. We propose that epidemiological models must incorporate climate effects through the AIR index.
    Language English
    Publishing date 2021-02-02
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472743-2
    ISSN 1089-7666 ; 1070-6631
    ISSN (online) 1089-7666
    ISSN 1070-6631
    DOI 10.1063/5.0037640
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: On respiratory droplets and face masks.

    Dbouk, Talib / Drikakis, Dimitris

    Physics of fluids (Woodbury, N.Y. : 1994)

    2020  Volume 32, Issue 6, Page(s) 63303

    Abstract: Face mask filters-textile, surgical, or respiratory-are widely used in an effort to limit the spread of airborne viral infections. Our understanding of the droplet dynamics around a face mask filter, including the droplet containment and leakage from and ...

    Abstract Face mask filters-textile, surgical, or respiratory-are widely used in an effort to limit the spread of airborne viral infections. Our understanding of the droplet dynamics around a face mask filter, including the droplet containment and leakage from and passing through the cover, is incomplete. We present a fluid dynamics study of the transmission of respiratory droplets through and around a face mask filter. By employing multiphase computational fluid dynamics in a fully coupled Eulerian-Lagrangian framework, we investigate the droplet dynamics induced by a mild coughing incident and examine the fluid dynamics phenomena affecting the mask efficiency. The model takes into account turbulent dispersion forces, droplet phase-change, evaporation, and breakup in addition to the droplet-droplet and droplet-air interactions. The model mimics real events by using data, which closely resemble cough experiments. The study shows that the criteria employed for assessing the face mask performance must be modified to take into account the penetration dynamics of airborne droplet transmission, the fluid dynamics leakage around the filter, and reduction of efficiency during cough cycles. A new criterion for calculating more accurately the mask efficiency by taking into account the penetration dynamics is proposed. We show that the use of masks will reduce the airborne droplet transmission and will also protect the wearer from the droplets expelled from other subjects. However, many droplets still spread around and away from the cover, cumulatively, during cough cycles. Therefore, the use of a mask does not provide complete protection, and social distancing remains important during a pandemic. The implications of the reduced mask efficiency and respiratory droplet transmission away from the mask are even more critical for healthcare workers. The results of this study provide evidence of droplet transmission prevention by face masks, which can guide their use and further improvement.
    Keywords covid19
    Language English
    Publishing date 2020-05-28
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472743-2
    ISSN 1089-7666 ; 1070-6631
    ISSN (online) 1089-7666
    ISSN 1070-6631
    DOI 10.1063/5.0015044
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: On coughing and airborne droplet transmission to humans.

    Dbouk, Talib / Drikakis, Dimitris

    Physics of fluids (Woodbury, N.Y. : 1994)

    2020  Volume 32, Issue 5, Page(s) 53310

    Abstract: Our understanding of the mechanisms of airborne transmission of viruses is incomplete. This paper employs computational multiphase fluid dynamics and heat transfer to investigate transport, dispersion, and evaporation of saliva particles arising from a ... ...

    Abstract Our understanding of the mechanisms of airborne transmission of viruses is incomplete. This paper employs computational multiphase fluid dynamics and heat transfer to investigate transport, dispersion, and evaporation of saliva particles arising from a human cough. An ejection process of saliva droplets in air was applied to mimic the real event of a human cough. We employ an advanced three-dimensional model based on fully coupled Eulerian-Lagrangian techniques that take into account the relative humidity, turbulent dispersion forces, droplet phase-change, evaporation, and breakup in addition to the droplet-droplet and droplet-air interactions. We computationally investigate the effect of wind speed on social distancing. For a mild human cough in air at 20 °C and 50% relative humidity, we found that human saliva-disease-carrier droplets may travel up to unexpected considerable distances depending on the wind speed. When the wind speed was approximately zero, the saliva droplets did not travel 2 m, which is within the social distancing recommendations. However, at wind speeds varying from 4 km/h to 15 km/h, we found that the saliva droplets can travel up to 6 m with a decrease in the concentration and liquid droplet size in the wind direction. Our findings imply that considering the environmental conditions, the 2 m social distance may not be sufficient. Further research is required to quantify the influence of parameters such as the environment's relative humidity and temperature among others.
    Keywords covid19
    Language English
    Publishing date 2020-06-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472743-2
    ISSN 1089-7666 ; 1070-6631
    ISSN (online) 1089-7666
    ISSN 1070-6631
    DOI 10.1063/5.0011960
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Reducing indoor virus transmission using air purifiers.

    Dbouk, Talib / Roger, Frederic / Drikakis, Dimitris

    Physics of fluids (Woodbury, N.Y. : 1994)

    2021  Volume 33, Issue 10, Page(s) 103301

    Abstract: Air purifiers are limited to small polluting airborne particles and poor air circulation (fan) for bringing airborne particles inside the device. Thus, the optimal utility of domestic air purifiers (DAPs) for eliminating airborne viruses is still ... ...

    Abstract Air purifiers are limited to small polluting airborne particles and poor air circulation (fan) for bringing airborne particles inside the device. Thus, the optimal utility of domestic air purifiers (DAPs) for eliminating airborne viruses is still ambiguous. This paper addresses the above limitations using computational fluid dynamics modeling and simulations to investigate the optimal local design of a DAP in an indoor space. We also investigate the integrated fan system and the local transport of airborne viruses. Three different scenarios of using standard DAP equipment (
    Language English
    Publishing date 2021-10-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472743-2
    ISSN 1089-7666 ; 1070-6631
    ISSN (online) 1089-7666
    ISSN 1070-6631
    DOI 10.1063/5.0064115
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Risk assessment of pollen allergy in urban environments.

    Dbouk, Talib / Visez, Nicolas / Ali, Samer / Shahrour, Isam / Drikakis, Dimitris

    Scientific reports

    2022  Volume 12, Issue 1, Page(s) 21076

    Abstract: According to WHO, by 2050, at least one person out of two will suffer from an allergy disorder resulting from the accelerating air pollution associated with toxic gas emissions and climate change. Airborne pollen, and associated allergies, are major ... ...

    Abstract According to WHO, by 2050, at least one person out of two will suffer from an allergy disorder resulting from the accelerating air pollution associated with toxic gas emissions and climate change. Airborne pollen, and associated allergies, are major public health topics during the pollination season, and their effects are further strengthened due to climate change. Therefore, assessing the airborne pollen allergy risk is essential for improving public health. This study presents a new computational fluid dynamics methodology for risk assessment of local airborne pollen transport in an urban environment. Specifically, we investigate the local airborne pollen transport from trees on a university campus in the north of France. We produce risk assessment maps for pollen allergy for five consecutive days during the pollination season. The proposed methodology could be extended to larger built-up areas for different weather conditions. The risk assessment maps may also be integrated with smart devices, thus leading to decision-aid tools to better guide and protect the public against airborne pollen allergy.
    MeSH term(s) Humans ; Rhinitis, Allergic, Seasonal/epidemiology ; Rhinitis, Allergic, Seasonal/etiology ; France/epidemiology ; Universities ; Risk Assessment
    Language English
    Publishing date 2022-12-06
    Publishing country England
    Document type Journal Article
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-022-24819-w
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Weather impact on airborne coronavirus survival.

    Dbouk, Talib / Drikakis, Dimitris

    Physics of fluids (Woodbury, N.Y. : 1994)

    2019  Volume 32, Issue 9, Page(s) 93312

    Abstract: The contribution of this paper toward understanding of airborne coronavirus survival is twofold: We develop new theoretical correlations for the unsteady evaporation of coronavirus (CoV) contaminated saliva droplets. Furthermore, we implement the new ... ...

    Abstract The contribution of this paper toward understanding of airborne coronavirus survival is twofold: We develop new theoretical correlations for the unsteady evaporation of coronavirus (CoV) contaminated saliva droplets. Furthermore, we implement the new correlations in a three-dimensional multiphase Eulerian-Lagrangian computational fluid dynamics solver to study the effects of weather conditions on airborne virus transmission. The new theory introduces a thermal history kernel and provides transient Nusselt (Nu) and Sherwood (Sh) numbers as a function of the Reynolds (Re), Prandtl (Pr), and Schmidt numbers (Sc). For the first time, these new correlations take into account the mixture properties due to the concentration of CoV particles in a saliva droplet. We show that the steady-state relationships induce significant errors and must not be applied in unsteady saliva droplet evaporation. The classical theory introduces substantial deviations in Nu and Sh values when increasing the Reynolds number defined at the droplet scale. The effects of relative humidity, temperature, and wind speed on the transport and viability of CoV in a cloud of airborne saliva droplets are also examined. The results reveal that a significant reduction of virus viability occurs when both high temperature and low relative humidity occur. The droplet cloud's traveled distance and concentration remain significant at any temperature if the relative humidity is high, which is in contradiction with what was previously believed by many epidemiologists. The above could explain the increase in CoV cases in many crowded cities around the middle of July (e.g., Delhi), where both high temperature and high relative humidity values were recorded one month earlier (during June). Moreover, it creates a crucial alert for the possibility of a second wave of the pandemic in the coming autumn and winter seasons when low temperatures and high wind speeds will increase airborne virus survival and transmission.
    Keywords covid19
    Language English
    Publishing date 2019-09-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472743-2
    ISSN 1089-7666 ; 1070-6631
    ISSN (online) 1089-7666
    ISSN 1070-6631
    DOI 10.1063/5.0024272
    Database MEDical Literature Analysis and Retrieval System OnLINE

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