Numerical Framework to Determine Instability Modes for Static Vehicles under Partial Submergence

Studies on instabilites of static (parked) vehicles that are partially submerged during flood events have captured worldwide attention in the previous years. The response of varying hydrodynamics effects to vehicles have been the interests reported. Indeed, the vehicle shapes have been found to significantly affect the response towards its hydrodynamics. These works, however, were experimental in nature. As the development of complex exterior designs of vehicles progressively made with the expansion of technologies, repeating the tedious experimental testing on another set of vehicle designs may not be practical. Herein this paper attempts to provide guidance on the use of a simple numerical framework to compensate the use of experimental testing. The proposed framework has been validated with a series of experimental testing conducted on a 1:24 scaled model that was controlled to be partially submerged under sub-critical conditions. Keeping close to the assumptions that the submergence levels of the vehicles are significantly influencing the buoyancy and drag forces, the numerical approach had given a simpler mechanism on the calculations of the submerged area (AD) and volume (V) of the vehicle, when this could not be computed easily during experiments. The parameters AD and V coupled with a graphical presentation of instability threshold values, would provide quick computations on the corresponding forces acting on the any similar characteristics static vehicle accordingly

EFFICIENCY O F GRASS PATTERNS ON SLOPE EROSION CONTROLS DUE TO RUNOFF

Soil erosion is a serious environmental, social, and economic problem which is not only responsible for the loss of soil productivity and severe land degradation but it also threatens the sustainable development of a society. It is associated with the onsite impacts which occurwhenthe land is degraded due to the loss of nutrient rich top layer causing adverse impacts to the soil quality. The off-site impacts are liable to water contamination and increased turbidity which are responsible for the environmental degradation and economic losses

The Impact of Providing Surface Cover on the Soil Loss and Water Discharge under the Moderate Rainfall Event

A nation’s development purely relies on the good road infrastructure which is necessary to promote the economic growth of the country. On the other side, the detrimental effects in the form of soil loss caused by its construction cannot be neglected. Roads, regardless of their small areal periphery are equally responsible to induce higher rates of erosion when compared with the agricultural lands. This study aimed to shelter the exposed soil surface once the gradients are constructed to mitigate undesirable siltation which raises water muddiness and worsens water carrying capacity of the stream channels. To cope with this issue a full scale field test was conducted on three plots which resembles the road embankments (~30°) provided with the different percentage of land covers i.e. Plot A (fully grass covered surface), Plot B (bare surface), and Plot C (50% of the grass covered surface). The soil loss examined was sandy loam. The sediment loss was observed manually at the catchment outlet of each plot whereas, the volume rate of water flow was observed in the designed bottom container. The runs were conducted for 2 hours under the simulated rainfall events of 52 mm hr-1. The impact of simulated rainfall on the soil loss was nullified by Plot A, the soil loss was severe for Plot B, and Plot C showed preeminent results in restricting soil from flowing away. Whereas, the values of water discharge were found varying for all the plots at different time intervals which are further discussed in this paper. Keywords: erosion by water, water discharge, exposed soil surface, land cover, simulated rainfal

Trend assessment of changing climate patterns over the major agro-climatic zones of Sindh and Punjab

The agriculture sector, due to its significant dependence on climate patterns and water availability, is highly vulnerable to changing climate patterns. Pakistan is an agrarian economy with 30% of its land area under cultivation and 93% of its water resources being utilized for agricultural production. Therefore, the changing climate patterns may adversely affect the agriculture and water resources of the country. This study was conducted to assess the climate variations over the major agro-climatic zones of Sindh and Punjab, which serve as an important hub for the production of major food and cash crops in Pakistan. For this purpose, the climate data of 21 stations were analyzed using the Mann–Kendall test and Sen's slope estimator method for the period 1990–2022. The results obtained from the analysis revealed that, in Sindh, the mean annual temperature rose by ~0.1 to 1.4°C, with ~0.1 to 1.2°C in cotton-wheat Sindh and 0.8 to 1.4°C in rice-other Sindh during the study period. Similarly, in Punjab, the mean annual temperature increased by ~0.1 to 1.0°C, with 0.6 to 0.9°C in cotton-wheat Punjab and 0.2 to 0.6°C in rainfed Punjab. Seasonally, warming was found to be highest during the spring season. The precipitation analysis showed a rising annual precipitation trend in Sindh (+30 to +60 mm) and Punjab (+100 to 300 mm), while the monsoon precipitation increased by ~50 to 200 mm. For winter precipitation, an upward trend was found in mixed Punjab, while the remaining stations showed a declining pattern. Conclusively, the warming temperatures as found in the analysis may result in increased irrigation requirements, soil moisture desiccation, and wilting of crops, ultimately leading to low crop yield and threatening the livelihoods of local farmers. On the other hand, the increasing precipitation may favor national agriculture in terms of less freshwater withdrawals. However, it may also result in increased rainfall-induced floods inundating the crop fields and causing water logging and soil salinization. The study outcomes comprehensively highlighted the prevailing climate trends over the important agro-climatic zones of Pakistan, which may aid in devising an effective climate change adaptation and mitigation strategy to ensure the state of water and food security in the country

Criterion of vehicle instability in floodwaters: past, present and future

This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of River Basin Management on January 2019, available online at: http://www.tandfonline.com/10.1080/15715124.2019.1566240The stability of vehicles exposed to floodwaters on the roads should not be taken for granted, especially in floodplain areas. When a vehicle in floodwaters becomes unstable, it tends to become buoyant and, eventually, is washed away, putting occupants in extreme danger. Therefore, the characteristics of vehicle instability in floodwaters should be critically understood to prepare safety guidelines. This paper attempts to summarize different vehicle stability studies, which focused on parked vehicles for a range of flood depths, through experimental and theoretical analysis (1967–1993). However, modern vehicle designs mean there are different values for the stability limits under partial or full submergence with different braking conditions, orientations and ground slopes (2010–2017). Since all the reported studies are about static vehicles, this paper attempts to address, for the very first time, vehicles in motion and endangered by floodwaters. As such, the governing effect of incipient velocity for a partially submerged, non-stationary vehicle will be presented, under the consideration of two new parameters, namely rolling friction and driving force.Peer ReviewedPostprint (author's final draft

Hazard risks pertaining to partially submerged non-stationary vehicle on low-lying roadways under subcritical flows

Rivers overflowing onto the floodplains can seriously disrupt the transportation system which can cause significant risks to moving or parked vehicles. The major flooding occurrence at the East Coast of Malaysia in December 2014 for instance, exhibited several hazards and fatalities involving vehicle submergence when the road conditions at low-lying flooded roadways were not known to the road users. To imitate a similar situation, the hydraulic characteristics of river overtopping an adjacent low-lying roadway during floods and the dynamics response of a vehicle attempting to cross over such flows were carried out in a modelled experimental set up. With that regards, a Perodua Viva which represents the medium-sized Malaysian passenger car was manufactured (1:10), ensuring similarity laws. Further, to monitor significant threats a flooded vehicle could face, the low-lying roadway model was designed to the allowable grade of five percent as proposed in Arahan Teknik (Jalan), ATJ 8/86. Keeping in view the height of the car and subcritical state of the flow, the range of water depths between 0.047 and 0.089 m, whereas for velocities, it was controlled to be in between 0.20 and 0.39 m/s, respectively. The buoyancy depth was noticed at depths greater than and equal to 0.055 m. Below critical depth, mode of sliding failure relied on the dominancy of varying horizontal pushing forces, namely frictional resistance, rolling friction, drag and driving forces.Peer ReviewedPostprint (published version

A review of safety guidelines for vehicles in floodwaters

This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of River Basin Management on 2019, available online at: http://www.tandfonline.com/10.1080/15715124.2019.1687487The development of guidelines for the design and analysis of street drainage systems to ensure safety of pedestrians and vehicles is an issue of fundamental importance. To prevent pedestrians and vehicles from being swept away during flooding events, the up to date guidelines are recommended in Australian Rainfall and Runoff (AR&R, 2011) report. These guidelines are based on the upper bounds on both depth and velocity; and the constant limiting velocity × depth (v·y) functions derived from the earlier works (1967–1993) associated with the stability of old-fashioned vehicles (static condition). The AR&R (2011) guideline does not include the assessment of the studies on modern vehicles (static) which were published very close or after its release (2010–2017). However, as a result of considerable modifications in the chassis design since those former investigations, several issues concerning stability of modern vehicles in floodwaters have been raised. Herein this paper ponders on both the limit functions highlighted in those earlier and recent works. Further, the reported works have highlighted that the studies performed on vehicles in the past were limited to static condition, therefore in this paper an attempt has been made to address hydrodynamic response of a non-static vehicle endangered by floodwaters. Thus, the algorithms of the hydrodynamic studies for the non-static vehicle into safe stability limits will be presented, under the consideration of few modified parameters, which involves the rolling resistance generated at vehicle tires, drag impact at vehicle’s front end and driving force caused by vehicle enginePeer ReviewedPostprint (author's final draft

Impact and Mitigation Strategies for Flash Floods Occurrence towards Vehicle Instabilities

This chapter presents a flood risk management system for vehicles at roadways, developed from extensive experimental and numerical studies on the impact of flash floods towards vehicle instabilities. The system, easily addressed as FLO-LOW, developed to contradict the assumptions that a vehicle would be able to protect the passengers from the flood impact. Herein the hydrodynamics of flows moving across these roads coupled with the conditions of a static car that would result in vehicle instabilities has been studied. In an attempt to prevent fatalities in commonly flooded areas, permanent structures are installed to warn users regarding water depth at the flooded areas. The existing flood monitoring system only focuses on water conditions in rivers or lake in order to determine risks associated with floods. Thus, there is a need for a better system to understand and quantify a mechanism to determine hydrodynamics instability of a vehicle in floodwaters. FLO-LOW enables the road users to input their vehicle information for a proper estimation of safety limits upon crossing the flood prone area. Preferably, the system enables road users to describe and quantify parameters that might cause their vehicles to become vulnerable to being washed away as they enter the flooded area

A Sustainable Indoor Air Quality Monitoring Approach through Potable Living Wall for Closed Confined Spaces: A Way Forward to Fight Covid19

The COVID-19 pandemic has greatly influenced various aspects of life, part of which has consequently paved the way toward improvements in building design criteria, especially for closed confined spaces. The closed confined spaces are directly proportional to the quantity and quality of the volatile organic compounds (VOCs) present in the atmosphere, from which human beings breathe. In managing the impact produced by VOCs, a practical, sustainable, economical and environmentally friendly concept of indoor living walls has become a prominent feature for improving the indoor air quality (IAQ) of closed confined spaces to efficiently reduce sick building syndrome (SBS) factors. In modification of common practice of ventilation systems, living wall technology leverages the natural ability of plants to purify indoor air quality by reducing air pollutants and allows the recycling of indoor air and the creation of a productive and inspiring environment. In this paper, the concept of a portable living wall through the use of a native plant species locally available in Sindh, Pakistan is introduced. Herein, the portable living concept was assessed by means of the design, construction, and data collection (testing and monitoring) of various environmental parameters carried out before and after the installation of the living wall. The study was monitored for 90 days, and analyses for various types of air pollutants were carried out in the environmental laboratory. During the monitoring period, the parameters humidity, VOCs, hazardous chemicals of concern (HCOC), CO2 and CO showed reductions in their values, with changes observed ranging from 61.5 to 58%, 0.66 to 0.01 ppm, 0.2 to 0.01 ppm, 1070 to 528 ppm and 0.2 to 0.01 ppm, respectively. The outcomes showed noticeable changes in air pollutants coupled with reductions in heating, ventilation and air conditioning (HVAC) energy consumption by up to 25%, mainly due to limited air requirements for ventilation