Controlling the Intensity of a Bathtub Vortex by Acting on the Upstream Flow

2014 ◽  
Author(s):  
Yann Recoquillon ◽  
Emmanuelle Andrès ◽  
Azeddine Kourta
Keyword(s):  
Water Level ◽  
Motor Vehicle ◽  
Ventilation System ◽  
Water Flow Rate ◽  
Drain Pipe ◽  
Air Core ◽  
Inlet Conditions ◽  
Lower Water Level ◽  
Bathtub Vortex ◽  
Upstream Flow

In a motor vehicle, the cowl box is a volume located at the bottom of the windshield. It collects rainwater and drains it to provide clean and dry air to the passenger compartment through the ventilation system. When rainwater is accumulated into the box, a bathtub vortex appears above the drain pipe. This vortex sucks up air into the pipe and creates an air core responsible of the decreased water drain rate in the pipe. It leads to an increased water level in the box and can cause a water overflow into the ventilation system. The behavior of this bathtub vortex has been experimentally studied using a simplified geometry representative of a real cowl box. The inlet water flow rate is controlled and a capacitive probe measures water level in the box. The flow has been studied using Particle Image Velocimetry to measure velocity field around the vortex. The flow pattern is described using these data. Due to geometry and inlet conditions, the upstream flow forces the vortex counter-clockwise. It is also responsible for a shift of the vortex axis from the drain axis. In this configuration, the upstream flow is strongly asymmetric and feeds the vortex using less than half the width of the box. Based on these observations, a device has been tested in order to reduce the vortex intensity and consequently the water level. Resulting velocity fields show a better distribution of the upstream flow. The vortex intensity is decreased up to 55% and the water level up to 53%. Despite there is still a vortex with an air core, the water level is therefore significantly reduced. These results are particularly interesting for the cowl box design: if this device can guarantee a lower water level, the cowl box depth can be reduced and space can be saved.

scholarly journals METHODOLOGY FOR HYDRAULIC CALCULATION OF RIVER REGULATION AND DETERMINATION OF DIKE PARAMETERS

2017 ◽  
Vol 16 (4) ◽  
pp. 298-303
Author(s):  
E. I. Mikhnevich
Keyword(s):  
Water Level ◽  
Water Flow Rate ◽  
Flood Plain ◽  
River Regulation ◽  
Hydraulic Calculation ◽  
Design Parameters ◽  
Flood Water ◽  
River Bed ◽  
Belt Width

Territory protection against flood water inundation and creation of polder systems are carried out with the help of protection dikes. One of the main requirements to the composition of polder systems in flood plains is a location of border dikes beyond meander belt in order to avoid their erosion when meander development occurs. Meander belt width can be determined on the basis of the analysis of multi-year land surveying pertaining top river-bed building and in the case when such data is not available this parameter is calculated in accordance with the Snishchenko formula. While banking-up a river bed a flooded area is decreasing and, consequently, water level in inter-dike space and rate of flood water are significantly increasing. For this reason it is necessary to locate dikes at a such distance from a river bed which will not cause rather high increase in water level and flow velocity in the inter-dike space. Methodology for hydraulic calculation of river regulation has been developed in order to substantiate design parameters for levee systems, creation of favourable hydraulic regime in these systems and provision of sustainability for dikes. Its main elements are calculations of pass-through capacity of the leveed channel and rise of water level in inter-dike space, and distance between dikes and their crest level. Peculiar feature of the proposed calculated formulae is an interaction consideration of channel and inundated flows. Their mass-exchanging process results in slowing-down of the channel flow and acceleration of the inundated flow. This occurrence is taken into account and coefficients of kinematic efficiency are introduced to the elements of water flow rate in the river channel and flood plain, respectively. The adduced dependencies for determination of a dike crest level (consequently their height) take into consideration a rise of water level in inter-dike space for two types of polder systems: non-inundable (winter) dikes with maximum spring flood rate and inundable (summer) dikes with summer-autumn flood rates. The proposed calculated formulae can be recommended for application at design organizations.

Sedimentary Cladocera as indicators of past water-level changes in shallow northern lakes

2011 ◽  
Vol 75 (3) ◽  
pp. 430-437 ◽  
Author(s):  
Liisa Nevalainen ◽  
Kaarina Sarmaja-Korjonen ◽  
Tomi P. Luoto
Keyword(s):  
Water Level ◽  
Lake Level ◽  
Water Levels ◽  
Sediment Record ◽  
Inference Model ◽  
Water Level Changes ◽  
Long Term Changes ◽  
Lower Water Level ◽  
The Relationship

AbstractThe usability of subfossil Cladocera assemblages in reconstructing long-term changes in lake level was examined by testing the relationship between Cladocera-based planktonic/littoral (P/L) ratio and water-level inference model in a surface-sediment dataset and in a 2000-yr sediment record in Finland. The relationships between measured and inferred water levels and P/L ratios were significant in the dataset, implying that littoral taxa are primarily deposited in shallow littoral areas, while planktonic cladocerans accumulate abundantly mainly in deepwater locations. The 2000-yr water-level reconstructions based on the water-level inference model and P/L ratio corresponded closely with each other and with a previously available midge-inferred water-level reconstruction from the same core, showing a period of lower water level around AD 300–1000 and suggesting that the methods are valid for paleolimnological and -climatological use.

scholarly journals Impact of Negative Pressure in a Room Due to Increased Airtightness in Residential Apartment Housing

2019 ◽  
Vol 111 ◽  
pp. 01094
Author(s):  
Yoshihiro Toriumi ◽  
Takashi Kurabuchi
Keyword(s):  
Negative Pressure ◽  
Ventilation System ◽  
Air Conditioner ◽  
Drain Pipe ◽  
Multiple Factors ◽  
Air Intake ◽  
The Impact

This study surveyed the impact of a negative pressure in a room in a highly airtight residential apartment with Class 3 ventilation (natural air intake and mechanical exhaust). The results of the study are as follows. 1) A room may reach an excessive level of negative pressure depending on how the ventilation system is used. 2) Noise from the drain pipe of a room air conditioner caused by negative pressure in the room is dependent on how the drain pipe is installed. 3) An experiment was conducted to investigate the mechanism of a seal break in a toilet trap. However, the seal did not break. Thus, seal breaks may be caused by multiple factors.

scholarly journals Abiotic factors driving cyanobacterial biomass and composition under perennial bloom conditions in tropical latitudes

Hydrobiologia ◽  
2021 ◽  
Vol 848 (4) ◽  
pp. 943-960
Author(s):  
Rayane F. Vanderley ◽  
Kemal A. Ger ◽  
Vanessa Becker ◽  
Maria Gabriela T. A. Bezerra ◽  
Renata Panosso
Keyword(s):  
Water Level ◽  
Abiotic Factors ◽  
Nitrogen Concentration ◽  
Cyanobacterial Blooms ◽  
Tropical Freshwaters ◽  
Effects Of Drought ◽  
Lower Water Level ◽  
Harmful Cyanobacterial Blooms ◽  
Cyanobacterial Biomass ◽  
The Ideal

AbstractWhile warming and eutrophication have increased the frequency and magnitude of harmful cyanobacterial blooms globally, the scenario for many eutrophic tropical freshwaters is a perennial year-round bloom. Yet, the drivers of persistent blooms are less understood when conditions such as light, temperature, and nutrients favor cyanobacteria growth year-round, and especially in regions facing recurrent periods of drought. In order to understand the drivers of cyanobacteria dominance, we assessed the abiotic conditions related to the abundance and dominance of the two dominant bloom-forming genera Raphidiopsis and Microcystis, in six shallow, man-made lakes located in the semiarid Northeastern region of Brazil during a prolonged regional drought. Lower water level corresponded to increased phosphorous and nitrogen concentration and, consequently, phytoplankton biomass. Cyanobacterial biomass was also proportional to phosphorus concentrations during year-round blooms. Yet, the two dominant cyanobacterial genera, Raphidiopsis and Microcystis, seldom co-occurred temporally and the switch between them was driven by water transparency. Our results illustrate the effects of drought induced water level reductions on the biomass and composition of cyanobacterial blooms in tropical shallow man-made lakes. Given the ideal year-round conditions (i.e., high light and temperature), droughts may be expected to intensify the risk and multitude of problems associated with eutrophication.

scholarly journals Numerical Modeling of Wave Reflection from Sloped Impermeable Seawalls Using the SPH Method: Case Study of Chabahar Port

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Behrouz Aghaei ◽  
Afshin Mohseni Arasteh ◽  
Kamran Lari ◽  
Masoud Torabi Azad
Keyword(s):  
Reflection Coefficient ◽  
Water Level ◽  
Wave Height ◽  
Wave Reflection ◽  
Wave Period ◽  
Water Level Fluctuations ◽  
Reflection Coefficients ◽  
Particle Hydrodynamics ◽  
Lower Water Level ◽  
Mike 21 Sw

In this research, a comprehensive study is performed to investigate the interaction of regular waves with the impermeable seawall of the Chabahar port. First, a MIKE 21 SW model is used to transform the deep-water wave data to the nearshore zone. Then, the interaction of waves with the seawall is simulated using a well-known numerical smoothed particle hydrodynamics model named DualSPHysics. After validating the numerical results with the experimental data, a parametric study is performed to evaluate the effects of the wave height, wave period, and the slope of the seawall on the water level fluctuations and the wave reflection coefficient. The results showed that increasing the wave height slightly decreases the reflection coefficient. Meanwhile, a direct relationship was found between the wave height and the water level fluctuations near the wall. Generally, increasing the wave period resulted in higher reflection coefficients and water level fluctuations. Both the reflection coefficient and the water level fluctuations are greatly dependent on the slope of the seawall. Steeper slopes resulted in higher reflection coefficients and lower water level fluctuations near the seawall.

scholarly journals Control of the Development of Swirling Airflow Dynamics and Its Impact on Biomass Combustion Characteristics

2017 ◽  
Vol 54 (3) ◽  
pp. 30-39 ◽  
Author(s):  
I. Barmina ◽  
R. Valdmanis ◽  
M. Zaķe
Keyword(s):  
Nozzle Diameter ◽  
Biomass Combustion ◽  
Heat Output ◽  
Complete Combustion ◽  
Combustion Dynamics ◽  
Air Supply ◽  
Flow Formation ◽  
Swirl Intensity ◽  
Inlet Conditions ◽  
Upstream Flow

AbstractThe development of the swirling flame flow field and gasification/ combustion dynamics at thermo-chemical conversion of biomass pellets has experimentally been studied using a pilot device, which combines a biomass gasifier and combustor by varying the inlet conditions of the fuel-air mixture into the combustor. Experimental modelling of the formation of the cold nonreacting swirling airflow field above the inlet nozzle of the combustor and the upstream flow formation below the inlet nozzle has been carried out to assess the influence of the inlet nozzle diameter, as well primary and secondary air supply rates on the upstream flow formation and air swirl intensity, which is highly responsible for the formation of fuel-air mixture entering the combustor and the development of combustion dynamics downstream of the combustor. The research results demonstrate that at equal primary axial and secondary swirling air supply into the device a decrease in the inlet nozzle diameter enhances the upstream air swirl formation by increasing swirl intensity below the inlet nozzle of the combustor. This leads to the enhanced mixing of the combustible volatiles with the air swirl below the inlet nozzle of the combustor providing a more complete combustion of volatiles and an increase in the heat output of the device.

scholarly journals Morphological Features of Plants on Ash Settling Ponds. Case Study

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 616
Author(s):  
Renata Gamrat ◽  
Sławomir Stankowski ◽  
Anna Jaroszewska
Keyword(s):  
Water Level ◽  
Phragmites Australis ◽  
Poa Pratensis ◽  
Plant Succession ◽  
Biological Traits ◽  
Settling Pond ◽  
Lower Water Level ◽  
Chemical Conditions ◽  
Settling Ponds

Owing to variable water conditions, chemical conditions of water or ash substrate, ash settling ponds belong to anthropogenic objects which do not easily undergo plant succession. However, there are plants exhibiting biological traits allowing colonisation of a substrate characterised by variability in terms of acidity and heavy metal content. The aim of the study was to determine differences in morphology of plants colonising spontaneous surfaces of ash settling ponds with variability moisture level. We identified also differences in morphology of the plants. Identified: Agrostis stolonifera, Atriplex patula, Juncus bufonius, Phragmites australis, Poa pratensis and Ranunculus sceleratus. The obtained results broaden the knowledge on the bioremediation of degraded areas, indicate species that inhabit the surface of ash settlers. Lower water level in ash settling pond I created more favourable conditions for growth of the aboveground parts of plants, and higher waterlevel in ash settling pond II contributed to a more intensive development of the root part of plants. Considering the generative factors and measurement values of the aboveground part of plants, the best adapted species were Juncus bufonius and Atriplex patula. Due to changing water level in ash settling ponds, the species to be monitored is Phragmites australis—most deeply colonising the surface of ash settling ponds.

Automated Operation With Redundant Ultrasonic Reactor Water Level Monitoring System

2009 ◽  
Author(s):  
Vahid Askari
Keyword(s):  
Water Level ◽  
Monitoring System ◽  
Water Flow Rate ◽  
Heat Removal ◽  
Free Water ◽  
Reactor Water ◽  
Emergency Procedures ◽  
Airborne Contamination ◽  
Level Monitoring ◽  
Water Level Monitoring

The proposed ultrasonic Reactor water Level Monitoring system is intended for monitoring water level in the hot leg of a nuclear reactor during Operation at Reduced Inventory (ORI) with the core in place as may be needed for certain maintenance activities. Since the existing fuel bundles continue the production of heat thorough the decay process, it is critical to maintain a certain water flow rate through the reactor. The Residual Heat Removal System (RHRS) handles this task during the reactor shutdown. The free water surface during ORI subjects the RHRS to the risk of air intake. Such an event would trigger a set of emergency procedures for priming the RHRS and bringing it back online. Some of the possible outcomes of such an event are: extension of outage, handling of the extra regulatory reporting tasks, potential requirements for extra testing after system recovery, possible damage to RHR pump, boiling of reactor water, generation of airborne contamination, and fuel damage. Another risk during ORI is reactor overflow. The major immediate concern is the safety of personnel in case of accidental overflow. This event could result in contamination and the related outage delays. The previously existing systems have always had problems with transducer reliability. This has lead to the need for removal and re-installation of their transducers from outage to outage. However, the proposed system uses a redundant design with permanently mounted transducers. The system uses advanced digital signal processing techniques to determine the water level.

scholarly journals Values of methane emission from drainage ditches

2012 ◽  
Vol 3 (2) ◽  
pp. 1-10 ◽  
Author(s):  
A A Sirin ◽  
G G Suvorov ◽  
M V Chistotin ◽  
M V Glagolev
Keyword(s):  
Water Level ◽  
Methane Emission ◽  
Water Flow Rate ◽  
Methane Flux ◽  
Drainage Area ◽  
Moscow Oblast ◽  
Emission Rates ◽  
Summer Period ◽  
Extraction Area ◽  
Methane Fluxes

Methane fluxes were measured from ditches on peatlands drained for different purposes in two testing areas in European part of Russia. We used static chamber method and gas chromatography for CH 4 analysis. In Moscow Oblast CH 4 emissions were measured from ditches on milled peat extraction area and on agricultural drainage area (used for haying) during 2005-2011. Ditch spacing for both sites is 40 m, width on water level – 1.5-2 m. Averaged (median) methane flux for summer period was 28.5 and 12.5 mgС-CH 4∙m –2∙h –1, respectively, at these sites. Averaged (median) methane flux for summer period was 28.5 and 12.5 mgС-CH 4∙m –2∙h –1 for these sites consequently. In 2009-2011 methane fluxes were also measured from the ditch on forest drainage area, upstream and downstream the dam built for mire restoration. Simple average CH 4 emission rate was much higher at tail-bay point with flowing water as compared with back point upstream the dam with stagnant water – 14.4 and 2.4 mgС-CH 4∙m –2∙h –1, consequently. We assume water flow rate supports water degassing and increase of CH 4 emission from ditches. In Tver Oblast methane flux was measured in 2010 from ditches on forested bog and on forested fen, both drained for forestry with ditch spacing approx. 100 m, and ditch width on water level – 1-1.5 m. Flux observed at first nutrient-poor site was much lower – 0.31 mgС-CH 4∙m –2∙h –1, as compared with nutrient-rich one – 3.88 mgС-CH 4∙m –2∙h –1. Using methane emission rates from ditches and fractional area of ditches we calculate emission factors from drained peatlands. The results showed rather high values which need to be considered while assessing GHG emissions from drained peatlands.

Experimental Study on Flow Conditions of Jiaogang Ship Lock during Sluice Gate Hoist

2013 ◽  
Vol 405-408 ◽  
pp. 1458-1462
Author(s):  
Teng Wu ◽  
Jian Ding
Keyword(s):  
Water Level ◽  
Spring Tide ◽  
Main Flow ◽  
Tidal Range ◽  
Flow Conditions ◽  
Sluice Gate ◽  
Lock Chamber ◽  
Approach Channel ◽  
Lower Water Level ◽  
Ship Lock

The physical model of Jiaogang Ship Lock is established. Through model test, the flow condition in lock chamber and approach channel is studied. The results indicate when the upstream water level keeps high and the water level difference between upstream and downstream is less than 0.5 meter, the main flow oscillates less during spring tide flux and reflux in the flood year. When the upper water level is 0.96 m and during spring tide flux and reflux in the flood year, the flow is from downstream to upstream and the flow is smooth. When the upper water level is greater than lower water level, the sluice gate hoist condition is tidal range less than 0.3m in tide flux and less than 0.4m in tide reflux. Under the critical water level conditions, the Jiaogang Ship Lock sluice gate can be hoisted safely.

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