Numerical Investigation on Flood Water Sloshing Influence on Intact and Damaged Stability of Ship

Sloshing affects the intact and damage stability of the ship, which causes variation in dynamic metacentric height (GM) under critical load conditions. The transient flooding soon after the ship damage is analyzed, with floodwater accumulation in large space and causing the ship to suffer huge heel angles. The ship motion and stability changes when sloshing becomes high in partially flooded compartments. Most of the previous researches focus on the motion response of ship alone, hence the variation of stability due to sloshing is to be more critically studied. In the present study, three critical damage locations are identified and flooding through these locations are analyzed using the volume of fluids method. The method focus on finding damage ship motion response, flood water dynamics, and coupled dynamics of both. This is studied using the numerical method FLOW3D. Motion and stability behaviour will be different for different damage locations; hence portside, starboard-side, and aft-end bottom damage cases are considered. The effect of compartment shape and damage location on motion response and stability of the damaged ship is highlighted.

Kinerja Filter Portabel Tepat Guna dalam Mereduksi Kekeruhan Air Banjir untuk Sanitasi atau MCK

During flood people had difficulties in obtaining clean water for sanitation (toilet). There was plenty of flood water but highly turbid. The water filter required electricity but its power outaged during flood. Filters usually used energy from electricity or gravity. This study evaluated the performance of a new handy-manually operated flood water portable filter. The standard of Permenkes No. 32/2017 was used as a reference. The flood water filter was pressurized by 0.025 kgf/cm2 and 0.051 kgf/cm2 and used local media: gravel, silica sand, anthracite, sponge. The results showed that pressure 0.025 kgf/cm2 was able to reduce turbidity from 220 NTU to 20.17 NTU with efficiency 90.83%. At 0.051 kgf/cm2 the filter was able to reduce turbidity from 220 NTU to 29.67 NTU with efficiency 86.52%. The pressure variation significantly affects the filtrate quality. The filter with pressure 0.025 kgf/cm2 could be applied for optimal filtration and produced 100-150 liters before clogging. This filter still needs to be studied related to physical strength, type and composition of media, portability and volume of water produced. This flood water filter will be an alternative solution for areas that often flood but no electricity or the power outage during flood.

THE TRANSIENT EFFECTS OF FLOOD WATER ON A WARSHIP IN CALM WATER IMMEDIATELY FOLLOWING DAMAGE

The safety of a ship which is damaged below the waterline will depend on the way water floods into the internal compartments. The water will cause the ship to take on an angle of heel and trim which will further affect the flooding into the compartments. The ship’s equilibrium position in calm water can be predicted using hydrostatic theory, however at present it is difficult to predict the transient behaviour between the initial upright position of the ship and its final equilibrium. In some cases, the transient motion may cause a capsize prior to a possible equilibrium position being reached. This paper describes an investigation of this phenomenon using a model of a warship with simplified, typical internal geometry. With the model initially stationary, a rapid damage event was generated, and the global motions measured, along with the water levels in some of the internal compartments, as functions of time. Immediately after the damage occurred the model rolled to starboard (towards the damage). It then rolled to port (away from the damage) before eventually returning to starboard and settling at its equilibrium value. In all the tests conducted the equilibrium heel angle was less than that reached during the initial roll to starboard. This implies that the roll damping, and the way in which the water floods into the model immediately following the damage, could both have a very important influence on the likelihood of survival.

URBAN FLOOD IMPACTS, FLOOD WATER QUALITY AND RISK MAPPING OF OLODO AREA, IBADAN, NIGERIA

This study assessed urban flood impact, flood water quality and vulnerability around Olodo area of Ibadan region, Nigeria. The study employed remote sensing and GIS techniques in creating vulnerability and risk maps. Digital terrain model (DTM) was used to get the topography of the study area. Footprints of buildings along the Egberi riverbank and flood plain in Olodo were created in the GIS environment from high resolution satellite imagery. Buffering operation was conducted to classify the buildings into risk zones based on closeness to the riverbank using ArcGIS 10.0. The study revealed that 326 buildings were within the very vulnerable and vulnerable zones because they were less than 15.2m away from the riverbank. The characteristics of water quality change during the flood and non-flood periods. TSS, DO, NOD, and COD were all higher during the flood event. Microbial analysis showed that water quality levels in the floodwater exceeded water quality standards (e.g., the coliform excess from 10 to 10,000 times), and thus this may be a health risk for local people during flood events. Concentration of Escherichia coli (E. coli) ranged from 484 to 1290 cfu/100 mL during flooding compared to 192 to 295 cfu/100 mL after flood. Salmonella was found to be high ranging from 659 to 1840 cfu/100 mL during flooding compared to 530 to 1034 cfu/100 mL after flooding.

Modeling of Flooding of Settlements During the Spring Flood

The problem of flooding of territories with flood waters for settlements of the Volgograd region is considered. A numerical model of flood water dynamics is constructed, taking into account the topography of the terrain. The simulation is based on two-dimensional shallow water equations. For computational experiments, a parallel implementation of the numerical scheme CSPH-TVD for NVIDIA graphics accelerators with CUDA technology is used. The digital model of the river-bed and floodplain relief is based on spatial data SRTM3 and SRTMGL, topographic maps of the area, longitudinal profiles of rivers. The water flow rates for the Buzuluk and Perevozinka rivers are determined and a hydrograph of the Volga hydroelectric power station is constructed for the given probabilities of exceeding the water level. Flood maps were obtained for the following localities: Novoannisky, Berezovka 1st, kh. Vyazovka. The maximum values of the depths for 1 %, 3 %, 5 %, 10 %, 25 % and 50 % of water security are presented. An analysis of the flood situation was carried out and appropriate engineering and protective measures for settlements were proposed. At maximum flood water levels, residential buildings of kh. Berezovka 1-I are not subject to flooding. In order to minimize the negative impact for the city of Novoanninsky, it is proposed to carry out timely clearing of the river-bed of the Perevozinka river from congestion. To protect from flooding ch. Vyazovka it is recommended to use diversion dyke.

Numerical modelling and computer visualization of the storm surge in and around the Croatan-Albemarle-Pamlico estuary system produced by hurricane Emily of August 1993

Hurricane Emily unleashed its fury on the Outer Banks of North Carolina on 31 August 1993. Storm surge was a major cause of damage along the Outer Banks. The highest flood water (11-11.5ft) occurred in the Buxton area near Cape Hatteras, North Carolina. It was reported that this flood water was from storm surges along the sound side of the barrier islands. An experimental forecast was conducted for this event in real time using Croatan-Albemarle-Pamlico estuary systems (CAPES) storm surge prediction model developed at North Carolina State University (NCSU). It uses as input parameters the projected hurricane track, minimum center pressure, maximum sustained wind speed and radius of maximum wind speed provided by the National Hurricane Center (NHC). The forcing of the model also includes fresh water input from sound system rivers, and of coastal waters intruding into the sound via Ocracoke, Hatteras and Oregon inlets. The predicted maximum surge along the sound side of the Outer Banks was within 85-90% of the post-storm highwater-mark survey data provided by the U.S. Geological Survey (USGS). Albeit, an after the fact simulation using the post-storm analysis of the track of Emily provided by the NHC, the maximum storm surge along the sound side of the Outer Bancks predicted by the model was within 95-98% of the maximum highwater mark data. The location of the predicted maximum surge for both pre and first model runs was near Cape Hatteras, which agreed well with USGS's survey data. We conclude that the CAPES storm surge model is capable of providing accurate storm surge forecasts in and around the CAPES, but such forecasts are sensitive to not only the observed storm size and intensity but in particular, the projected storm track.

Lifting Kit for Flooded Furnitures: Mechanical Design and Strength Analysis

<p>Almost every year, floods disaster becomes the scourge of many countries in the world, including Indonesia. When the flood comes and submerges the houses, every item and household furniture in it will also be submerged in flood water. Furniture that is heavy and difficult to move, especially electronic equipment such as refrigerators, may be left by the owner when a flood occurs. To prevent the furniture from submerging, a lifting kit is needed. For this reason, the purpose of this work is to design a mechanical tool/kit that can lift or elevate the electronic furniture such as refrigerator to a higher position and avoid the damage caused by flood. The kit is expected to be able to cover a 100 x 80 cm base of the refrigerator with maximum load of 200 kg. The elevation of the lifting kit is set to be higher than 50 cm. Calculation for the stress and fatigue analysis is also performed to determine the strength of the structure. As a result, the obtained safety factors for the critical components under static and fatigue loading conditions show values of more than one, indicating the product is safe for real operation. In addition, the required torque to produce the elevation is also calculated and discussed.</p>