Overview of Research on the Influence of Permeable Structures

2013 ◽  
Vol 405-408 ◽  
pp. 2115-2122
Author(s):  
Qian Qian Shang ◽  
Hui Xu ◽  
Guo Bin Li
Keyword(s):  
Water Flow ◽  
Flow Condition ◽  
River Regulation ◽  
Adverse Impact ◽  
Local Flow ◽  
Flow Energy ◽  
Similarities And Differences ◽  
Protective Structures

The protective structures on the shore often used in the river regulation and channel rectification works are divided into solid structures and permeable structures. The solid structures will cause an intensive change of the local flow condition, and lead to adverse impact as scouring of local foundation and edges; the permeable structures which can dissipate the flow energy are gradually popularized for use. Common permeable structures include the tetrahedron-like penetrating frame used for engineering and vegetation on the shore, etc. This paper takes the tetrahedron-like penetrating frame and vegetation for example, summarizes research on the behavior of water flow and sediment affected by permeable structures, discusses the similarities and differences as well as different effects of the functions of the solid structures and permeable structures, and finally concludes the features of application of permeable structures.

scholarly journals Water flow energy harvesters for autonomous flowmeters

2016 ◽  
Vol 773 ◽  
pp. 012019 ◽  
Author(s):  
Sebastien Boisseau ◽  
Alexandre-Benoit Duret ◽  
Matthias Perez ◽  
Emmanuel Jallas ◽  
Eric Jallas
Keyword(s):  
Water Flow ◽  
Energy Harvesters ◽  
Flow Energy

Clarifying the Interrelations of Residents’ Perceived Tourism-Related Stress, Stressors, and Impacts

2019 ◽  
Vol 60 (1) ◽  
pp. 208-219 ◽  
Author(s):  
Evan J. Jordan ◽  
Laura Lesar ◽  
Daniel M. Spencer
Keyword(s):  
Adverse Impact ◽  
Health And Wellness ◽  
Tourism Impact ◽  
Tourism Impacts ◽  
Similarities And Differences ◽  
Related Stress ◽  
As Stress

While stress has recently been documented as an adverse impact of tourism, it has not been examined alongside traditional tourism impacts to determine their similarities and differences. To clarify the interrelations of these phenomena, we explored whether tourism-related stressors were similar to well-known tourism impacts, and whether perceived tourism impacts increased the likelihood of experiencing tourism-related stress. Residents of O’ahu, Hawai’i, were asked how much tourism impacted them on 36 variables, whether tourism caused them stress, and if so, how. Study findings reveal that tourism-related stressors often correspond with what have been traditionally considered tourism impacts. Moreover, only five of the tourism impact variables predicted the experience of tourism-related stress, and of these only one was a frequently cited stressor. Connecting impacts to stressors expands the possibility that certain tourism impacts could have consequences that go beyond mere opinions and attitudes, as stress has many health and wellness consequences.

Influences of Impeller Diameter and Diffuser Blades on Air-Water Two-Phase Flow Performance of Centrifugal Pump

2005 ◽  
Author(s):  
Naoki Matsushita ◽  
Akinori Furukawa ◽  
Kusuo Okuma ◽  
Satoshi Watanabe
Keyword(s):  
Centrifugal Pump ◽  
Water Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Flow Condition ◽  
High Performance ◽  
Two Phase Flow ◽  
Water Flow Rate ◽  
Phase Flow ◽  
Two Phase

A tandem arrangement of double rotating cascades and single diffuser cascade, proposed as a centrifugal pump with high performance in air-water two-phase flow condition, yields lower head due to the smallness of the impeller outlet in comparison with a impeller with large outlet diameter and no diffuser. Influences of impeller diameter change and installation of diffuser blades on two-phase flow performance were experimentally investigated under the case of the same volute casing. As the result, the similarity law of the diameter of impeller having the similar blade geometry and the rotational speed is satisfied even in two-phase flow condition. Comparing pump performances between a large impeller without diffuser blades and a small one with diffuser blades, higher two-phase flow performance is obtained by controlling the rotational speed of a small impeller with diffuser blades in the range of small water flow rates, while a large impeller with no diffuser gives high performance in the range of high water flow rate and small air flow rate.

scholarly journals PENGARUH VARIASI JARAK ANTARA KATUP LIMBAH DENGAN KATUP PENGHANTAR TERHADAP EFISIENSI POMPA HIDRAM PVC 2 INCHI PARAREL

2020 ◽  
Vol 5 (1) ◽  
pp. 37-41
Author(s):  
Defmit B.N Riwu ◽  
Dominggus G. H. Adoe ◽  
Seprianus Rudolf Membubu
Keyword(s):  
Potential Energy ◽  
Water Flow ◽  
Driving Force ◽  
Water Sources ◽  
Long Distance ◽  
Flow Energy

Abstrak Pompa hidram merupakan salah satu jenis pompa yang tidak membutuhkan energi listrik atau bahan bakar. Energi potensial dari sumber air yang dialirkan sebagai daya penggerak. Dimana alat ini bekerja pada sumber air yang memiliki kemiringan, sebab alat ini membutuhkan energi terjunan air dari ketinggian lebih besar atau sama dengan 1 meter yang masuk ke dalam pompa. Dalam pengoperasinya pompa ini mempunyai keuntungan yaitu dengan menggunakan pipa PVC yang dengan sederhana merancangnya juga dapat dibuat dengan peralatan bengkel. Penelitian ini dilakukan untuk mengetahui pengaruh variasi jarak antara katup limbah dengan katup penghantar terhadap efisiensi pompa hydram. Metode yang digunakan adalah experimen lapangan dengan beberapa perubahan pada variasi jarak antara katup limbah dengan katup penghantar adalah 10 cm, 20 cm,30 cm. Dari hasil penelitian bahwa debit pemompaan optimum mengalami peningkatan pada ukuran pendek yaitu 0,00011633 m3/detik, debit limbah semakin besar pada ukuran jarak panjang yaitu 0,00086013 m3/detik, dengan jumlah ketukan terjadi yaitu 84 kali. Sehingga efisiensi hidram menurut teori d’aubussion diperoleh hasil tertinggi yaitu 71,02 %. Kata Kunci: Pompa hidram 2 inchi, double katup limbah, katup penghantar, dan efisiensi D’aubuission Abstract Hydram pump is one type of pump that does not require electricity or fuel. Potential energy from water sources that is channeled as a driving force. Where this tool works at a source of water that has a slope, because this tool requires water flow energy from a height greater than or equal to 1 meter into the pump. In the operation of this pump has the advantage of using PVC pipes which are simple to design can also be made with workshop equipment. This research was conducted to determine the effect of variations in the distance between the waste valve and the delivery valve on the efficiency of the hydram pump. The method used is a real experimental with some changes in the variation of the distance between the waste valve and the delivery valve is 10 cm, 20 cm, 30 cm. From the results of the study that the optimum pumping discharge increased in the short size of 0.00011633 m3 / second, the greater the discharge of waste at a long-distance size of 0.00086013 m3 / second, with the number of beats occurring at 84 times. So that the efficiency of hydrams according to the theory of 'aubussion obtained the highest yield of 71.02%. Keywords: 2-inch hydram pump, double valve waste, delivery valve, and D'obuission efficiency.

An Underwater Magnetically Coupled Bistable Vibration Energy Harvester Using Wings

2019 ◽  
Author(s):  
Hong-Xiang Zou ◽  
Ke-Xiang Wei ◽  
Lin-Chuan Zhao ◽  
Wen-Ming Zhang ◽  
Lei Zuo ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Water Flow ◽  
Energy Harvester ◽  
High Reliability ◽  
Average Power ◽  
Vibration Energy ◽  
Coupling Mechanism ◽  
Vibration Energy Harvester ◽  
Water Flow Velocity ◽  
Flow Energy

Abstract Piezoelectric flow energy harvesting can be a potential way to yield endless electrical energy for small mechanical systems and wireless sensors. We propose a novel magnetically coupled bistable vibration energy harvester using wings for the applications in the water environment. The water flow energy can be harvested through the induced vibration of wings. The flextensional transducer can be packaged conveniently by using non-contact magnetic coupling mechanism. The magnetic force is amplified by the flextensional structure and transferred to the piezoelectric layer, thereby achieving higher power density and better reliability. A prototype was fabricated and tested in a water flume, which attended a maximum power of about 400 μW and the average power of 55 μW at the water flow velocity of 4 m/s. No significant variation occurred to the performance of the harvester after five days of continuous operation in the water, which indicates that the magnetically coupled vibration energy harvesting method has high reliability in the underwater environment.

scholarly journals Occurrence, Classification and Formation Mechanisms of the Organic-Rich Clasts in the Upper Paleozoic Coal-Bearing Tight Sandstone, Northeastern Margin of the Ordos Basin, China

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2694
Author(s):  
Guanqun Yang ◽  
Wenhui Huang ◽  
Jianhua Zhong ◽  
Ningliang Sun
Keyword(s):  
Water Flow ◽  
Higher Plants ◽  
Ordos Basin ◽  
Formation Mechanisms ◽  
Tight Sandstone ◽  
Flow Energy ◽  
Sedimentary Environments ◽  
Upper Paleozoic ◽  
The Ordos Basin ◽  
Thin Interlayer

The detailed characteristics and formation mechanisms of organic-rich clasts (ORCs) in the Upper Paleozoic tight sandstone in the northeastern margin of the Ordos Basin were analyzed through 818-m-long drilling cores and logging data from 28 wells. In general, compared with soft-sediment clasts documented in other sedimentary environments, organic-rich clasts in coal-bearing tight sandstone have not been adequately investigated in the literature. ORCs are widely developed in various sedimentary environments of coal-bearing sandstone, including fluvial channels, crevasse splays, tidal channels, sand flats, and subaqueous debris flow deposits. In addition to being controlled by the water flow energy and transportation processes, the fragmentation degree and morphology of ORCs are also related to their content of higher plants organic matter. The change in water flow energy during transportation makes the ORCs show obvious mechanical depositional differentiation. Four main types of ORC can be recognized in the deposits: diamictic organic-rich clasts, floating organic-rich clasts, loaded lamellar organic-rich clasts, and thin interlayer organic-rich clasts. The relationship between energy variation and ORCs deposition continuity is rarely studied so far. Based on the different handling processes under the control of water flow energy changes, we propose two ORCs formation mechanisms: the long-term altering of continuous water flow and the short-term water flow acting triggered by sudden events.

Phase-averaged Tomographic PIV Measurements for a Surface Combatant in Pure Sway Maneuver

2017 ◽  
Author(s):  
Hyunse Yoon ◽  
Frederick Stern
Keyword(s):  
Volume Visualization ◽  
Static Condition ◽  
Core Analysis ◽  
Flow Measurements ◽  
Local Flow ◽  
Tomographic Piv ◽  
Test Conditions ◽  
Uncertainty Estimates ◽  
Surface Combatant ◽  
Similarities And Differences

Forces and moment and phase-averaged Tomographic PIV (TPIV) local flow measurements are performed in a 3 m × 3 m × 100 m towing tank for a 3.048-m long geometrically similar model of surface combatant 5415 in pure sway maneuver. Test conditions are for maximum drift angle 𝛽max = 10° and Froude number Fr = 0.28. The TPIV enables fully volumetric flow measurements and the use of 𝑄-criteria enables vortex volume visualization and core analysis. The objective of the experiment is to extend the knowledge for the static condition vortex separation onset and progression to unsteady dynamic conditions, including integrated CFD. Test conditions meet the IITC criteria for sway frequency and restricted water restrictions. Both the present and previous uncertainty assessment (UA) for forces and moment show acceptable values. The uncertainty estimates for TPIV is done by using a practical approach and the results are comparable with the earlier UA using a conventional approach. Integrated CFD simulations are used to identify flow vortices. The comparison with the previous TPIV results for static maneuver conditions show improvements for the present TPIV using a more advanced algorithm. The pure sway measurements at phases corresponding to straight-ahead and 𝛽max = 10° show similarities and differences with the static maneuver measurements, whereas at intermediate phases substantial vortex interactions and unsteady separation onset and progression is shown. The vortex core analysis shows similarities and differences in the core strength and trajectory with the static drift and dynamic pure yaw maneuvers. The present experiment is ongoing and the initial measurement results and analysis are discussed herein.

Shrub morpho-types as indicator for the water flow energy - Tivoli travertine case (Central Italy)

2017 ◽  
Vol 347 ◽  
pp. 79-99 ◽  
Author(s):  
Marcelle Marques Erthal ◽  
Enrico Capezzuoli ◽  
Alessandro Mancini ◽  
Hannes Claes ◽  
Jeroen Soete ◽  
...  
Keyword(s):  
Water Flow ◽  
Central Italy ◽  
Flow Energy
Sign in / Sign up

Export Citation Format

Share Document