Browsing by Author "Singh, L."

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    Assessing the impact of damage and government response toward the cyclone Gaja in Tamil Nadu, India
    (Elsevier, 2021) Devanantham, D.; Subbarayan, S.; Jennifer, J.J.; Kulithalai Shiyam Sundar, K.S.S.; Singh, L.; Sankriti, R.
    The cyclone is one of the most frequently occurring natural disaster in all tropical countries that interrupts the socioeconomic development. In India, the rate of cyclone occurrence has increased by almost 30%. Tamil Nadu state, India, becomes one of the most cyclone-prone regions in the country. Severe cyclonic storm Gaja made landfall on 16th November 2018 in Nagapattinam district in Tamil Nadu. It had sustained wind speeds of 100-110 km/h with gusts of up to 120 km/h. The storm brought a significant amount of rainfall of about 140-170 mm. According to the reports, 45 people lost their lives, and 76, 290 people were evacuated from low-lying areas and sheltered in 300 relief centers. In this study, we have discussed strategies on the response after the event, preparedness, relief, recovery operations, rehabilitation, reconstruction, violent conflicts, economic sustainability, infrastructure development, livelihood, and the cause for severe damage and resilience. © 2021 Elsevier Inc. All rights reserved.
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    Dispersion in an Urban Cross-Street Intersection
    (Springer Science and Business Media Deutschland GmbH, 2025) Ranadive, S.; Singh, L.; Jitendra Pal, S.
    A typical urban street intersection comprises of roadways, pedestrian walkways, and tall buildings on the sides. Due to the large number of vehicles plying on the urban streets, the pedestrians are exposed to vehicular pollution. With the increase in the density of automobiles, there is a bigger threat to pedestrians. The current study investigates pollution dispersion in the case of an eight-story building across a cross-street intersection. The study includes the effect of the aspect ratio (AR = 0.5, AR = 1, and AR = 2), a ratio of building height to road width, on flow patterns and dispersion. The second part of the work includes the effect of wind approach angle (0º, 30º, 45º, 60º) on the dispersion. It is found that the pollutant mass concentration at the nose level of pedestrians is strongly influenced by the aspect ratio wherein the taller building provides less exposure to pedestrians due to the lateral dispersion. The wind approach angle also affects the pollutant concentration at the nose level. The exposure to pollutant is skewed along the length of the road walkways in the case of 30º and 60º. However, the dispersion in more uniform in the case when wind approach angle is 45º. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.
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    GIS-based multi-criteria analysis for identification of potential groundwater recharge zones - a case study from Ponnaniyaru watershed, Tamil Nadu, India
    (KeAi Communications Co., 2020) Devanantham, D.; Subbarayan, S.; Singh, L.; Jennifer, J.J.; Saranya, T.; Kulithalai Shiyam Sundar, K.S.S.
    Groundwater is one of the most vital natural resources; spatially varying in quality and quantity. Increased urbanisation and population creates tremendous pressure on the quality and quantity of the groundwater resources. In this study, Ponnaniyaru watershed of Cauvery basin was considered for this research. Geographical information system (GIS) and remote sensing (RS) plays a vital role in preparing various thematic layers for targeting the groundwater potential zones (GWPZ). This study adopts the Analytical Hierarchy Process (AHP) and Multi influence factor (MIF), multi-criteria decision-making approaches to determine the weights for the influencing factors. Weighted linear overlay analysis was carried out to determine the GWPZ. Further, the resultant GWPZ map has been reclassified into five different classes, namely Very good, Good, Moderate, Poor and Very poor. The results were validated with observed well-yield data, and the predictive precision for AHP and MIF was found to be 75%, and 71% respectively. © 2020 The Authors
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    Impact of Building Configurations on Fluid Flow in an Urban Street Canyon
    (Springer Science and Business Media Deutschland GmbH, 2024) Singh, S.; Singh, L.; Jitendra Pal, S.
    The problem of pollution dispersion in urban areas is significant in the densely populated cities. The topography and barriers in the form of buildings impact the atmospheric fluid flow. The resulting phenomena known as pollution traps cause an artificial dispersion in the buildings’ proximity, affecting the health of ordinary road commuters. The primary source of pollution on the street canyons is exhaust gases from the vehicle movements. However, the concern is associated with the poor dispersion of pollutants under normal wind conditions. The primary reason behind the poor dispersion is the buildings that act as obstacles to the atmospheric wind flow. Thereby it is essential to comprehend the behaviour of pollutants under given shape constraints and flow conditions to improve urban air quality. The present study investigates the wind flow in the proximity of a six-storey building for a medium street canyon configuration under the logarithm inlet velocity profile that acts as atmospheric boundary layer (ABL). Effect of important parameters such as the building height, the wind direction (0, 30, 45, 60, and 90°), and building configurations (straight road, both side building, and only upwind side building with downwind side building) are investigated to gain valuable insights into pollutant dispersion. The analysis of turbulence and velocity profile in the domain at nose level (1.5 m above ground level) leeward sidewalk and windward sidewalk shows turbulent intensity decreases at the nose (breathing) level with building height; however, it increases when the approach angle is 450 suggesting the formation of dominant pockets of pollutants. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
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    Wind Pattern and Dispersion in a T-Intersection Street Canyon
    (Springer Science and Business Media Deutschland GmbH, 2024) Udupi, S.K.; Rao, R.; Mahesh, S.; Tiwari, C.; Singh, L.; Pal, S.J.
    Each year there has been a steady rise in vehicles plying on roads leading to an increase in roadside pollution. The condition is grimmer in urban sectors and metro cities. The dispersion of vehicular pollution is essential for the health of pedestrians and nearby societies. Factors like street canyon geometry and meteorological conditions play a significant role in dispersing pollution. One of a typical urban road settings includes a T-intersection canyon having buildings alongside it. The current work attempts to numerically study the wind pattern in the proximity of a T-intersection street configuration. The study investigates the effect of incoming wind velocities and building aspect ratio on the turbulence levels and flow zones adjoining the street canyon. It is observed that the flow regime for the configuration when the ratio of building height and street is one is skimming, while the bulk flow does not enter the canyon. The changes in the configuration lead to variations in the formation of distinct vortexes that are stable and isolated. The analysis of velocity profiles shows sharp gradients at the tip of the building but tends to decrease slowly away from the ground. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.