DRAG COEFFICIENT OF A SOLID SPHERE UNDER NON-ISOTHERMAL CONDITIONS

2021 ◽  
pp. 13-24
Author(s):  
V.A. Arkhipov ◽  
◽  
S.A. Basalaev ◽  
K.G. Perfilieva ◽  
A.S. Usanina ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Reynolds Numbers ◽  
Solid Sphere ◽  
Analysis Method ◽  
Carrier Medium ◽  
Gravitational Settling ◽  
Isothermal Conditions ◽  
The Difference ◽  
Solid Spheres ◽  
Stationary Velocity

The results of an experimental study of gravitational settling of a cooled (T = 82 K, 250 K) and a heated (T = 373 K, 473 K, 573 K) steel ball in glycerin and polymethylsiloxane liquids (PDMS-10000, PDMS-30000) in the range of the Reynolds numbers Re = 10−3–1 are presented. It is shown that the stationary velocity of gravitational settling of a particle decreases with its cooling and, conversely, it increases with heating of the particle. A time dependence of the distance traveled by the particle is found to be linear for both heated, cooled, and etalon (T = Tl) solid spheres. The effect of the difference in the particle and carrier medium temperatures on the drag coefficient of the solid sphere is analyzed. For the considered Reynolds numbers, it is revealed that the drag coefficient of a single solid sphere is determined by CD = a /Re , where a is the empirical coefficient depending on the ratio of the particle and liquid temperatures T = T /Tl . Using the regression analysis method, the expression for a drag coefficient of a solid particle under non-isothermal conditions at T >> 1 is found to be similar to the Hadamard –Rybczynski expression CD = 16/Re, which is obtained for a spherical bubble (or a drop). The empirical dependences of the drag coefficient for a cooled and a heated solid sphere on the difference in the particle and liquid temperatures δТ = 1− T are obtained.

Drag coefficient of a sphere in a non-stationary flow: new results

2007 ◽  
Vol 463 (2088) ◽  
pp. 3323-3345 ◽  
Author(s):  
G Jourdan ◽  
L Houas ◽  
O Igra ◽  
J.-L Estivalezes ◽  
C Devals ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Stationary Flow ◽  
Reynolds Numbers ◽  
Spherical Particles ◽  
Steady Flows ◽  
Two Phase ◽  
Spider Web ◽  
Wide Range ◽  
The Difference ◽  
Sphere Drag

The drag coefficient of a sphere placed in a non-stationary flow is studied experimentally over a wide range of Reynolds numbers in subsonic and supersonic flows. Experiments were conducted in a shock tube where the investigated balls were suspended, far from all the tube walls, on a very thin wire taken from a spider web. During each experiment, many shadowgraph photos were taken to enable an accurate construction of the sphere's trajectory. Based on the sphere's trajectory, its drag coefficient was evaluated. It was shown that a large difference exists between the sphere drag coefficient in steady and non-steady flows. In the investigated range of Reynolds numbers, the difference exceeds 50%. Based on the obtained results, a correlation for the non-stationary drag coefficient of a sphere is given. This correlation can be used safely in simulating two-phase flows composed of small spherical particles immersed in a gaseous medium.

Flow past a flat plate at low Reynolds numbers

1958 ◽  
Vol 3 (4) ◽  
pp. 329-343 ◽  
Author(s):  
E. Janssen
Keyword(s):  
Reynolds Number ◽  
Drag Coefficient ◽  
Flat Plate ◽  
Truncation Error ◽  
Reynolds Numbers ◽  
Experimental Result ◽  
Total Drag ◽  
Low Reynolds Numbers ◽  
Flow Past ◽  
The Difference

The flow past a flat plate at Reynolds numbers in the range 0·1 to 10·0 is investigated by an analogue method. The solution gives the stream function and the vorticity in the flow field surrounding the plate. From these are obtained the local coefficient of friction, the pressure distribution along the plate, and the total drag coefficient. The drag coefficient approaches the analytical values of Haaser (1950) and of Tomotika & Aoi (1953) as the Reynolds number decreases toward 0·1. The drag coefficient approaches the Blasius solution as the Reynolds number increases. At Reynolds number 10·0 the drag coefficient is still above the Blasius value, but is below the value obtained experimentally by Janour (1951). The difference from the experimental result is attributed for the most part to truncation error.

The motion of a solid sphere suspended by a Newtonian or viscoelastic jet

1996 ◽  
Vol 315 ◽  
pp. 367-385 ◽  
Author(s):  
J. Feng ◽  
D. D. Joseph
Keyword(s):  
Flow Field ◽  
Physical Mechanism ◽  
Reynolds Numbers ◽  
Solid Sphere ◽  
Normal Stresses ◽  
Low Reynolds Numbers ◽  
Laminar Jet ◽  
Local Shear ◽  
Available Information ◽  
Solid Spheres

This paper describes experimental observations of a solid sphere suspended by a vertical or inclined jet. A laminar Newtonian jet is able to suspend a sphere only through viscous entrainment at low Reynolds numbers (Re ~ 10). A turbulent Newtonian jet (Re ~ 104) attracts a sphere that is sufficiently large but rejects smaller ones. The Coanda effect is responsible for steady suspension of solid spheres even in highly slanted jets. Anomalous rotation, opposite to the direction of the local shear, occurs under certain conditions, and its physical mechanism cannot be explained based on available information. A viscoelastic laminar jet is narrower than a comparable Newtonian one and it can suspend spheres at Reynolds numbers in the hundreds, precisely the Re range in which a Newtonian jet fails to suspend a sphere. It is suggested that the contrast between laminar Newtonian and viscoelastic jets may be related to a reversal in the pressure distribution on the surface of the sphere caused by non-Newtonian normal stresses. Flow visualization provides insights into the flow field in the jet and around the solid sphere.

Implementasi Sistem Informasi Monitoring Pengolahan Data Inventory Gudang Pada PT.Talaga Mulya Indah

2020 ◽  
Vol 6 (2) ◽  
pp. 187-197
Author(s):  
Nurlaila Suci Rahayu Rais ◽  
Dedeh Apriyani ◽  
Gito Gardjito
Keyword(s):  
Data Processing ◽  
Integrated Control ◽  
Unified Modeling Language ◽  
Review Literature ◽  
Analysis Method ◽  
Inventory Data ◽  
Literature Study ◽  
Unified Modeling ◽  
The Difference ◽  
The Right

Monitoring of warehouse inventory data processing is an important thing for companies. PT Talaga mulya indah is still manual using paper media, causing problems that have an effect on existing information, namely: problems with data processing of incoming and outgoing goods. And the difference between data on the amount of stock of goods available with physical data, often occurs inputting data more than once for the same item, searching for available data, and making reports so that it impedes companies in monitoring inventory of existing stock of goods. Which aims to create a system that can provide updated information to facilitate the warehouse admin in making inventory reports, and reduce errors in input by means of integrated control. In this study, the authors used the data collection method used in this analysis using the method of observation, interviews, and literature review (literature study). For analysis using the PIECES analysis method. Furthermore, the system design used is UML (Unified Modeling Language). The results of this study are expected to produce the right data in the process of monitoring inventory data processing, also can provide the right information and make it easier to control the overall availability of goods.

Pandhawa Gubah sebagai Representasi Interaksi Metafisik Manusia Jawa dan Perbandingannya dengan Cheritera Pandawa Lima

Manuskripta ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 67
Author(s):  
Novarina Novarina
Keyword(s):  
Comparative Study ◽  
Literary Theory ◽  
Research Method ◽  
Descriptive Analysis ◽  
Literary Study ◽  
Analysis Method ◽  
Research Objects ◽  
Similarities And Differences ◽  
The Difference ◽  
The Comparative Study

Abstract: This research is a comparative literary study that uses Malay and Javanese versions of Mahabarata text sources. The research objects used were the text edition of Pandhawa Gubah (PG) by Sudibjo Z. Hadisutjipto and the text of Cheritera Pandawa Lima (CPL) by Khalid Hussain. The research method used is descriptive-analysis method. In the comparative study used a comparative literary theory proposed by Endraswara (2011). The results of the text comparison reveal the similarities and differences in the image of Bima figures in the Javanese and Malay versions. The equation as a whole is that both texts contain the same heroic storyline and heroic character, Bima. In addition, Indian influence is still evident in the two texts seen from the nuances of Hinduism that exist in both texts. While the difference is seen in the events that accompany Bima's struggle in achieving his victory. Based on these similarities and differences, it can be seen that the authors attempt to represent the concept of metaphysical interactions vertically and horizontally expressed through PG text. --- Abstrak: Penelitian ini adalah satu kajian sastra bandingan yang menggunakan sumber teks Mahabarata versi Melayu dan Jawa. Objek penelitian yang digunakan adalah edisi teks Pandhawa Gubah (PG) karya Sudibjo Z. Hadisutjipto dan teks Cheritera Pandawa Lima (CPL) karya Khalid Hussain. Metode penelitian yang digunakan adalah metode deskriptif-analisis. Dalam telaah perbandingan digunakan teori sastra bandingan yang dikemukakan Endraswara (2011). Hasil perbandingan teks mengungkapkan adanya persamaan dan perbedaan citra tokoh Bima dalam versi Jawa maupun versi Melayu. Persamaan secara keseluruhan adalah kedua teks tersebut mengandung alur cerita kepahlawanan dan tokoh pahlawan yang sama yaitu Bima. Selain itu, pengaruh India masih tampak dalam kedua teks tersebut dilihat dari nuansa Hinduisme yang ada dalam kedua teks. Sementara perbedaannya tampak pada peristiwa-peristiwa yang menyertai perjuangan Bima dalam mencapai kemenangannya. Berdasarkan persamaan dan perbedaan tersebut tampak adanya upaya penulis untuk merepresentasikan konsep interaksi metafisik secara vertikal dan horizontal yang diungkapkan melalui teks PG.

Kesalahan Penggunaan Bahasa Perancis dalam Tulisan Mahasiswa Program Studi Sastra Perancis Unpad

Metahumaniora ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 368
Author(s):  
Gilang Januarsyah
Keyword(s):  
General Public ◽  
Qualitative Approach ◽  
French Language ◽  
Analysis Method ◽  
Writing Skill ◽  
Language Writing ◽  
The Difference ◽  
Observation Method ◽  
Bahasa Indonesia

ABSTRAKUntuk menghasilkan sebuah karangan berbahasa Perancis yang dapat dipahamioleh khalayak umum, mahasiswa harus menguasai kemampuan berbahasa Perancis ragamtulis yang baik dan benar sesuai dengan kaidah yang berlaku. Penelitian ini bertujuanuntuk menjelaskan kesalahan sintaksis yang dilakukan oleh mahasiswa Program StudiSastra Perancis Universitas Padjadjaran. Data yang digunakan dalam penelitian ini diambildari sepuluh karangan mahasiwa yang duduk di semester lima dan tujuh dan dianalisisdengan menggunakan metode simak dan metode analisis padan referensial translasionaldengan pendekatan kualitatif. Hasil dari penelitian ini menunjukkan bahwa kesalahantertinggi yang dilakukan mahasiswa adalah kesalahan dalam penggunaan passé composédan imparfait sebesar 50%, kemudian diikuti oleh kesalahan dalam penggunaan pronomrelatif simple et composé ‘pronomina penghubung bebas dan turunan’ sebesar 30%, danterakhir kesalahan dalam penggunaan pronom COD et COI ‘pronomina COD dan COI’ sebesar20%. Faktor yang menyebabkan terjadinya kesalahan tersebut adalah faktor linguistikyang disebabkan oleh perbedaan kaidah tatabahasa bahasa Indonesia dan Perancis.Selain itu terdapat pula faktor sosiolinguistik yang disebabkan oleh jarangnya mahasiswamembiasakan diri mereka untuk mengaplikasikan bahasa Perancis di luar kelas.Kata kunci: kesalahan, sintaksis, bahasa Perancis, tulis, pengajaranABST RACTTo produce a French-language essay that can be understood by the general public,the students should master the ability of French language in good and true writing skill inaccordance with the applicable rules. The aim of this research is to explain the syntactic errorsmade by students of French literature’s program at University Padjadjaran. The sources ofdata are taken from the ten student essays who sit in the fifth and seventh semesters, and themethods used in this research are Observation Method ‘Metode Simak’ and the analyticalreference translational analysis method with a qualitative approach. The results of thisresearch indicate that the highest errors that students make are the use of passé composéand imparfait as much as fifty percent, followed by errors in the use of pronom relatifsimple et composé ‘the free and derivative pronouns’ thirty percent, and the last error is inthe use of pronom CO D et CO I ‘‘The COD and COI pronouns’ twenty percent. The factors thatcause those errors are a linguistic caused by the difference rules of Indonesian and Frenchgrammar. In addition there are also sociolinguistic factors caused by the rarity of studentsfamiliarize themselves to apply the French language outside the classroom.Keywords: Error, syntax, French language, writing, teaching

Experimental investigations of flow over NACA airfoils 0021 and 4412 of wind turbine blades with and without Tubercles

2021 ◽  
pp. 0309524X2110071
Author(s):  
Usman Butt ◽  
Shafqat Hussain ◽  
Stephan Schacht ◽  
Uwe Ritschel
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Wind Turbine ◽  
Critical Region ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Leading Edge ◽  
Reynolds Numbers ◽  
Experimental Investigations ◽  
Wind Turbine Blades

Experimental investigations of wind turbine blades having NACA airfoils 0021 and 4412 with and without tubercles on the leading edge have been performed in a wind tunnel. It was found that the lift coefficient of the airfoil 0021 with tubercles was higher at Re = 1.2×105 and 1.69×105 in post critical region (at higher angle of attach) than airfoils without tubercles but this difference relatively diminished at higher Reynolds numbers and beyond indicating that there is no effect on the lift coefficients of airfoils with tubercles at higher Reynolds numbers whereas drag coefficient remains unchanged. It is noted that at Re = 1.69×105, the lift coefficient of airfoil without tubercles drops from 0.96 to 0.42 as the angle of attack increases from 15° to 20° which is about 56% and the corresponding values of lift coefficient for airfoil with tubercles are 0.86 and 0.7 at respective angles with18% drop.

Preparation of hollow Fe3O4 spheres through a facile method and their applications

2017 ◽  
Vol 10 (06) ◽  
pp. 1750075 ◽  
Author(s):  
Xingping Wu ◽  
Aiping Zhu ◽  
Zhaodong Nan
Keyword(s):  
Saturation Magnetization ◽  
Ostwald Ripening ◽  
Solvothermal Method ◽  
Hollow Spheres ◽  
Hollow Structure ◽  
Solid Sphere ◽  
Small Particles ◽  
Potential Applications ◽  
One Step ◽  
Solid Spheres

Fe3O4 hollow microspheres with good dispersibility and high saturation magnetization were synthesized through a facile one-step solvothermal method. The formation mechanism of the hollow structure was studied by taking time-dependent experiments. Porous [Formula: see text]-FeOOH and [Formula: see text]-Fe2O3 nanosheets were firstly fabricated. Fe3O4 solid spheres aggregated by small particles were obtained from the transition of [Formula: see text]-FeOOH and [Formula: see text]-Fe2O3. Finally, the solid sphere is transferred to hollow sphere through Ostwald ripening. The maximum saturation magnetization of the hollow spheres is [Formula: see text][Formula: see text]emu/g, which is higher than some results reported in references. The Fe3O4 hollow spheres show potential applications in microwave absorption and photocatalysis.

scholarly journals The Profile Drag of Yawed Wings of Infinite Span

1951 ◽  
Vol 3 (3) ◽  
pp. 211-229 ◽  
Author(s):  
A.D. Young ◽  
T.B. Booth
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Drag Coefficient ◽  
Experimental Evidence ◽  
Flat Plate ◽  
Transition Point ◽  
Reynolds Numbers ◽  
External Pressure ◽  
Basic Assumptions ◽  
Angle Of Yaw

SummaryA method is developed for calculating the profile drag of a yawed wing of infinite span, based on the assumption that the form of the spanwise distribution of velocity in the boundary layer, whether laminar or turbulent, is insensitive to the chordwise pressure distribution. The form is assumed to be the same as that accepted for the boundary layer on an unyawed plate with zero external pressure gradient. Experimental evidence indicates that these assumptions are reasonable in this context. The method is applied to a flat plate and the N.A.C.A. 64-012 section at zero incidence for a range of Reynolds numbers between 106 and 108, angles of yaw up to 45°, and a range of transition point positions. It is shown that the drag coefficients of a flat plate varies with yaw as cos½ Λ (where Λ is the angle of yaw) if the boundary layer is completely laminar, and it varies as if the boundary layer is completely turbulent. The drag coefficient of the N.A.C.A. 64-012 section, however, varies closely as cos½ Λ for transition point positions between 0 and 0.5 c. Further calculations on wing sections of other shapes and thicknesses and more detailed experimental checks of the basic assumptions at higher Reynolds numbers are desirable.

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