scholarly journals Numerical Study on the Hydrologic Characteristic of Permeable Friction Course Pavement

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 843
Author(s):  
Tan Hung Nguyen ◽  
Jaehun Ahn
Keyword(s):  
Numerical Analysis ◽  
Water Flow ◽  
Rainfall Intensity ◽  
Numerical Study ◽  
Geometric Design ◽  
Porous Asphalt ◽  
Pavement Surface ◽  
Design Charts ◽  
Hydrologic Characteristic ◽  
Water Overflow

The hydrologic characteristic of a permeable friction course (PFC) pavement is dependent on the rainfall intensity, pavement geometric design, and porous asphalt properties. Herein, the hydrologic characteristic of PFC pavements of various lengths and slopes was determined via numerical analysis. A series of analyses was conducted using length values of 10, 15, 20, and 30 m and slope values of 0.5%, 2%, 4%, 6%, and 8% for the equivalent water flow path. The PFC pavements were simulated for various values of rainfall intensity, which ranged from 10 to 120 mm/h, to determine the time taken for water to flow over the PFC pavement surface. The results show that the time for water overflow decreased when the pavement length or rainfall intensity increased, and it increased when the slope increased. Finally, a series of design charts was developed to determine the time taken for water to flow over the PFC pavement surface for given rainfall intensities. Since this study was conducted based on numerical analysis, further studies are recommended to verify experimentally the results presented.

The Effect of the Thickness and Angle of the Inlet and Outlet Guide Vane on the Performance of Axial-Flow Pump

2016 ◽  
Author(s):  
Sang-Won Kim ◽  
Youn-Jea Kim
Keyword(s):  
Numerical Analysis ◽  
Numerical Study ◽  
Guide Vane ◽  
Axial Flow ◽  
Inlet Guide Vane ◽  
Guide Vanes ◽  
Pump Performance ◽  
Blade Thickness ◽  
Axial Flow Pump ◽  
Flow Pump

An axial-flow pump has a relatively high discharge flow rate and specific speed at a relatively low head and it consists of an inlet guide vane, impeller, and outlet guide vane. The interaction of the flow through the inlet guide vane, impeller, and outlet guide vane of the axial-flow pump has a significant effect on its performance. Of those components, the guide vanes especially can improve the head and efficiency of the pump by transforming the kinetic energy of the rotating flow, which has a tangential velocity component, into pressure energy. Accordingly, the geometric configurations of the guide vanes such as blade thickness and angle are crucial design factors for determining the performance of the axial-flow pump. As the reliability of Computational Fluid Dynamics (CFD) has been elevated together with the advance in computer technology, numerical analysis using CFD has recently become an alternative to empirical experiment due to its high reliability to measure the flow field. Thus, in this study, 1,200mm axial-flow pump having an inlet guide vane and impeller with 4 blades and an outlet guide vane with 6 blades was numerically investigated. Numerical study was conducted using the commercial CFD code, ANSYS CFX ver. 16.1, in order to elucidate the effect of the thickness and angle of the guide vanes on the performance of 1,200mm axial-flow pump. The stage condition, which averages the fluxes between interfaces and is accordingly appropriate for the evaluation of pump performance, was adopted as the interface condition between the guide vanes and the impeller. The rotational periodicity condition was used in order to enable a simplified geometry to be used since the guide vanes feature multiple identical regions. The shear stress transport (SST) k-ω model, predicting the turbulence within the flow in good agreement, was also employed in the CFD calculation. With regard to the numerical simulation results, the characteristics of the pressure distribution were discussed in detail. The pump performance, which will determine how well an axial-flow pump will work in terms of its efficiency and head, was also discussed in detail, leading to the conclusion on the optimal blade thickness and angle for the improvement of the performance. In addition, the total pressure loss coefficient was considered in order to investigate the loss within the flow paths depending on the thickness and angle variations. The results presented in this study may give guidelines to the numerical analysis of the axial-flow pump and the investigation of the performance for further optimal design of the axial-flow pump.

scholarly journals ANALISIS BANJIR KELURAHAN TANJUNG DUREN SELATAN

2020 ◽  
Vol 3 (3) ◽  
pp. 569
Author(s):  
Natanael Tadeus Sutanto ◽  
Wati Asriningsih Pranoto
Keyword(s):  
Water Resources ◽  
Natural Disasters ◽  
Water Flow ◽  
Channel Capacity ◽  
Rainfall Intensity ◽  
Chi Square ◽  
Channel Condition ◽  
Direct Measurements ◽  
Kolmogorov Smirnov ◽  
City Water

Flood is one of the natural disasters that occur due to various factors and causes many losses. Tanjung Duren Selatan village was recorded as having floods in January 2020. This research aims to determine the causes of the flood in the area as well as the solution. The data obtained were taken from BMKG, West Jakarta City Water Resources Department, and direct measurements in the review area. This research analyzed rainfall, channel capacity, channel condition dan topography in Tanjung Duren Selatan village. Rainfall is tested for data compatibility using Chi-Square and Kolmogorov-Smirnov methods. Rainfall intensity is calculated using the Mononobe formula. The capacity of the existing channels is analyzed using Manning formula that will be compared with the planned discharge calculated using Rasional method. The analysis included secondary channels and tertiary channels, based on the calculation of 8 of the 48 channels reviewed that were unable to accommodate the planned discharge. After the analysis, it can be concluded that the flooding in Tanjung Duren Selatan village was caused by the lack of existing channel capacity, contours, and rubbish that blocked the water flow. Floods that occurred on January 1, 2020 due to rainfall that occurred exceeded the planned rainfall.ABSTRAKBanjir merupakan salah satu bencana alam yang terjadi akibat berbagai faktor dan menimbulkan banyak kerugian. Di Kelurahan Tanjung Duren Selatan tercatat mengalami banjir pada bulan Januari 2020. Penelitian ini bertujuan untuk mengetahui faktor penyebab terjadinya banjir pada daerah tersebut serta solusinya. Data-data yang didapat diambil dari BMKG, Suku Dinas Sumber Daya Air Kota Jakarta Barat, serta pengukuran langsung di daerah tinjauan. Pada penelitian ini dianalisis curah hujan, kapasitas saluran, kondisi saluran, serta topografi di Kelurahan Tanjung Duren Selatan. Curah hujan di uji kecocokan datanya menggunakan metode Chi-Square dan Kolmogorov-Smirnov. Intensitas curah hujan di hitung menggunakan rumus Mononobe. Kapasitas saluran eksisting di analisis menggunakan rumus Manning yang akan dibandingkan dengan debit rencana yang dihitung menggunakan metode Rasional. Analisis yang dilakukan mencakup saluran sekunder dan saluran tersier, berdasarkan perhitungan 8 dari 48 saluran yang ditinjau tidak mampu menampung debit rencana. Setelah analisis dilakukan dapat disimpulkan bahwa banjir di Kelurahan Tanjung Duren Selatan disebabkan oleh kurangnya kapasitas saluran eksisting, kontur, serta sampah yang menghalangi aliran air. Banjir yang terjadi pada tanggal 1 Januari 2020 dikarenakan curah hujan yang terjadi melebihi curah hujan rencana.

scholarly journals Research on Drain and Counter-Clogging Ability of Porous Asphalt Mixture

2015 ◽  
Vol 9 (1) ◽  
pp. 962-967
Author(s):  
Hongchang Wang ◽  
Minggang Zhou ◽  
Ming Li ◽  
Kunitomo Sugiura
Keyword(s):  
Design Parameter ◽  
Traffic Noise ◽  
Asphalt Mixture ◽  
Mixture Design ◽  
Driving Safety ◽  
Aggregate Gradation ◽  
Porous Asphalt ◽  
Pavement Surface ◽  
The World

Porous asphalts pavement arouses the attentions of the world by its good performance such as reduce the potential for hydroplaning, reduce splash and spray, improve visibility, decline traffic noise, and improve driving safety. But the void clogging lessens its durable function. So in this paper appropriate clogging agent was choose, and seepage coefficients were tested by using asphalt mixture pavement surface permeameter to simulation multi-cycle drainage clogging test. The influence of asphalt mixture design parameter such as the porosity, the maximum sizes of the aggregate, gradation and asphalt on the drainage and counter-clogging ability of porous asphalts was researched. The tests indicated that the porosity has an obvious influence on both porous asphalts’ permeable ability and counter-clogging ability. Comparing the specimen of 21% void to the ones of 16% void, the drain ability is improved 49.8%, the counter-clogging ability is improved 55.0%. The maximum sizes of the aggregate has an obvious influence on porous asphalts’ counter-clogging ability, but no an obvious influence on the drain ability. Comparing the specimen of 16mm to the 13mm, the counterclogging ability is proved 48%. PAC with the coarser graduation has a better performance on drain and counter-clogging ability. TPS modifier changes PAC little on drain and counter-clogging ability.

scholarly journals Experimental and Numerical Study of Pre-Swirl Stators PSS

2020 ◽  
Vol 8 (1) ◽  
pp. 47 ◽  
Author(s):  
Kourosh Koushan ◽  
Vladimir Krasilnikov ◽  
Marco Nataletti ◽  
Lucia Sileo ◽  
Silas Spence
Keyword(s):  
Numerical Analysis ◽  
Energy Saving ◽  
Scale Effect ◽  
Financial Incentives ◽  
Numerical Study ◽  
Considerable Improvement ◽  
Scale Model ◽  
Propulsion Efficiency ◽  
Wake Field ◽  
Additional Resistance

Energy saving within shipping is gaining more attention due to environmental awareness, financial incentives, and, most importantly, new regional and international rules, which limit the acceptable emission from the ships considerably. One of the measures is installation of energy saving devices (ESD). One type of such a device, known as pre-swirl stator (PSS), consists of a number (usually 3 to 5) of fins, which are mounted right in front of the propeller. By modifying the inflow and swirl into the propeller, the fins of a PSS have the possibility to increase the total propulsion efficiency. However, at the same time, they may introduce additional resistance either due to changes in pressure distribution over the aft ship or due to its own resistance of fins. In this paper, the authors present experimental and numerical investigation of a PSS for a chemical tanker. Numerical analysis of the vessel with and without PSS is performed in the model and full scale. Model testing is performed with and without PSS to verify the power savings predicted numerically. Among other quantities, 3D wake field behind the hull is densely measured at different planes, starting from the PSS plane to the rudder stock plane. 3D wake measurements are also conducted with a running propeller. The measurements show considerable improvement in the performance of the vessel fitted with PSS. On the numerical side, analyses show that scale effect plays an important role in the ESD performance. Investigation of the scale effect on the vessel equipped with an ESD provides new insight for the community, which is investing more into the development of energy saving devices, and it offers valuable information for the elaboration of scaling procedures for such vessels.

A Numerical Study on Flow Characteristics Through Orifice Flowmeter and Measurement Accuracy Depending on Upstream Straight Length

2017 ◽  
Author(s):  
Jang Il Lee ◽  
Ae Ju Cheong ◽  
Bok Ki Min
Keyword(s):  
Numerical Analysis ◽  
Measurement Accuracy ◽  
Performance Test ◽  
Swirling Flow ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Orifice Plate ◽  
3 Dimensional ◽  
Ansys Cfx ◽  
Axial Velocity Profile

In this numerical study, Commercial CFD (Computational Fluid Dynamics) code, ANSYS CFX ver. 17.1, is used to analyze the 3-Dimensional flow characteristics through orifice plate (β = 0.6) with two 90 degree bends in different planes. The purpose of this numerical study is to evaluate measurement accuracy and flow characteristics of orifice flowmeter depending on upstream straight length from 12D to 56D. Thus, numerical calculations of pressure drop caused by swirling flow and distortion of axial velocity profile on orifice plate are performed by using numerical analysis. In addition, numerical analysis results are compared with recommended upstream straight length of ASME Performance Test Codes 19.5 for orifice plates and nozzles. The results show that if upstream straight length of orifice flowmeter is more than 40D, there is a little deviation of differential pressure. Moreover, it is found that up-down asymmetry of recirculation zones is relatively attenuated as the upstream straight length increases.

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