scholarly journals CÓDIGO LIVRE PARA SOLUÇÃO NUMÉRICA DAS EQUAÇÕES DE SAINT-VENANT EM CANAIS TRAPEZOIDAIS ASSIMÉTRICOS

2020 ◽  
Vol 8 (2) ◽  
pp. 145
Author(s):  
Italon Rilson Vicente Gama ◽  
André Luiz Andrade Simões ◽  
Harry Edmar Schulz ◽  
Rodrigo De Melo Porto
Keyword(s):  
Hydraulic Jump ◽  
Rectangular Channel ◽  
Maximum Deviation ◽  
Practical Result ◽  
Trapezoidal Channel ◽  
Saint Venant Equations ◽  
Practical Engineering ◽  
Maximum Relative Deviation ◽  
The Mean ◽  
Average Position

<p>Ondas de cheia em canais e ondas produzidas por manobras em comportas são alguns fenômenos simulados com as equações de Saint-Venant em aplicações de engenharia. Um novo código foi desenvolvido para a solução dessas equações aplicadas a um canal trapezoidal assimétrico, empregando o método de volumes finitos de Lax e Friedrichs. Foi adotada uma linguagem de programação reconhecida por um <em>software</em> livre. Três testes numéricos foram realizados. O primeiro, correspondente à passagem de uma onda de cheia em um canal retangular, apresentou aderência aos resultados obtidos com a solução calculada através do método implícito de Preissmann, com desvio relativo máximo de 1,4% para a velocidade e de 0,81% para a altura de escoamento. O segundo teste resolveu o escoamento em um canal de fundo variado que induz à formação de um ressalto hidráulico. As comparações dos presentes resultados com aqueles de simulações publicadas recentemente resultaram em um desvio máximo de 2,3% para as alturas de escoamento, a montante e a jusante do ressalto hidráulico. Para as posições médias do ressalto hidráulico, o desvio foi de 2,4%. Na terceira comparação, simulou-se um ressalto hidráulico em um canal trapezoidal assimétrico de forte declividade, tendo sido encontrada uma solução com desvios relativos menores que 1% para os escoamentos a montante e a jusante do ressalto, quando comparados aos resultados calculados com o método de MacCormack. A posição média do ressalto nesta terceira comparação apresentou um desvio de 5,5% em relação aos resultados anteriores. Os desvios calculados indicam que o código desenvolvido é capaz de resolver escoamentos variáveis em canais com e sem a formação de ressaltos hidráulicos. Este é um resultado de cunho prático, pois mostra que códigos livres podem ser usados na prática da hidráulica em geometrias não-convencionais.</p><p> </p><p align="center">OPEN SOURCE FOR NUMERICAL SOLUTION OF SAINT-VENAN EQUATIONS IN ASYMMETRIC TRAPEZOIDAL OPEN-CHANNELS</p><p>Flood waves in channels, positive waves produced when operating floodgates, and the hydraulic jump are some phenomena simulated with the Saint-Venant equations in practical engineering applications. A new code was developed to solve these equations applied to an asymmetric trapezoidal channel using the Lax-Friedrichs finite volumes method. A programming language recognized by a free software was used. Three numerical tests were performed. The first, corresponding to the passage of a flood wave in a rectangular channel, showed adherence to results of the solution calculated using the Preissmann implicit method, presenting a maximum relative deviation of 1.4% for the speed and 0.81% for the flow height. The second test solved the flow in a channel with a variable bed that induces the formation of a hydraulic jump. Comparisons of the present results with those of recently published simulations produced a maximum deviation of 2.3% for the flow heights, upstream and downstream of the hydraulic jump. For the mean positions of the hydraulic jump the deviation was 2.4%. In the third comparison a hydraulic jump was simulated in an asymmetric trapezoidal channel with a strong slope, obtaining a solution with relative deviations less than 1% for flows upstream downstream of the jump, when compared to the results calculated with the MacCormack method. The average position of the jump in this third comparison showed a deviation of 5.5% in relation to the former results. The calculated deviations indicate that the developed code is capable of solving variable flows in channels with and without the formation of hydraulic jumps. This is a practical result, because it shows that open codes can be used in the practice of hydraulics in nonconventional geometries.</p>

Numerical Simulation of Hydraulic Jump Using the Improved Space-Time Conservation Element and Solution Element Method

2014 ◽  
Vol 575 ◽  
pp. 790-799
Author(s):  
Hoong Thiam Toh
Keyword(s):  
Cross Sections ◽  
Hydraulic Jump ◽  
Rectangular Channel ◽  
Space Time ◽  
Channel Cross Section ◽  
Saint Venant Equations ◽  
Dam Break Flow ◽  
Solution Element ◽  
Wall Slope ◽  
Good Agreement

This paper illustrates how Space-time Conservation Element and Solution Element (CE/SE) method which is developed for compressible flow can be used to solve the Saint-Venant equations numerically. The sharp shock-capturing capability of the scheme is demonstrated through the simulation of hydraulic jump phenomenon in prismatic open-channels. Two channel cross-section geometries are considered, viz rectangular and triangular cross sections. The code developed for the present study is validated by solving the benchmark problem of dam-break flow. The numerical solution of the Saint-Venant equations for the rectangular channel is found to be in good agreement with the experimental data available in the literature. The effect of channel wall slope on hydraulic jump in triangular channel is also discussed in this paper.

scholarly journals Crystal structure of bis(azido-κN)bis[2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole-κ2N2,N3]cobalt(II)

2015 ◽  
Vol 71 (5) ◽  
pp. 452-454 ◽  
Author(s):  
Abdelhakim Laachir ◽  
Fouad Bentiss ◽  
Salaheddine Guesmi ◽  
Mohamed Saadi ◽  
Lahcen El Ammari
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Title Complex ◽  
Octahedral Coordination ◽  
Maximum Deviation ◽  
Coordination Geometry ◽  
Acta Cryst ◽  
Π Interactions ◽  
The Mean

In the mononuclear title complex, [Co(N3)2(C12H8N4S)2], the cobalt(II) atom is located on an inversion centre and displays an axially weakly compressed octahedral coordination geometry. The equatorial positions are occupied by the N atoms of two 2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole ligands, whereas the axial positions are occupied by N atoms of the azide anions. The thiadiazole and pyridine rings linked to the metal are almost coplanar, with a maximum deviation from the mean plane of 0.0273 (16) Å. The cohesion of the crystal is ensured by weak C—H...N hydrogen bonds and by π–π interactions between pyridine rings [intercentroid distance = 3.6356 (11) Å], forming a layered arrangement parallel to (001). The structure of the title compound is isotypic with that of the analogous nickel(II) complex [Laachiret al.(2013).Acta Cryst.E69, m351–m352].

scholarly journals Crystal structure of triethyl 2-(5-nitro-2H-indazol-2-yl)propane-1,2,3-tricarboxylate

2015 ◽  
Vol 71 (10) ◽  
pp. o780-o781 ◽  
Author(s):  
Mohammed Boulhaoua ◽  
Mohammed Benchidmi ◽  
El Mokhtar Essassi ◽  
Mohamed Saadi ◽  
Lahcen El Ammari
Keyword(s):  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Site Occupancy ◽  
Maximum Deviation ◽  
Compound C ◽  
Carboxylate Groups ◽  
Dimensional Network ◽  
Fused Ring ◽  
The Mean ◽  
Fused Ring System

In the title compound, C19H23N3O8, the 5-nitro-2H-indazol-2-yl unit is almost planar, with the maximum deviation from the mean plane being 0.024 (2) Å. The fused-ring system is nearly perpendicular to the three carboxylate groups, with dihedral angles of 90.0 (3), 83.8 (1) and 80.4 (1)°. The ethyl groups attached to both ends of the propane chain are each disordered over two sets of sites, with site-occupancy ratios of 0.425 (17):0.575 (17) and 0.302 (15):0.698 (15). In the crystal, molecules are linked by pairs of C—H...N hydrogen bonds, forming inversion dimers. The dimers are further linked by C—H...O hydrogen bonds, forming a three-dimensional network.

scholarly journals Crystal structure of (7-methyl-2-oxo-2H-chromen-4-yl)methyl piperidine-1-carbodithioate

2015 ◽  
Vol 71 (8) ◽  
pp. o606-o607
Author(s):  
K. R. Roopashree ◽  
T. G. Meenakshi ◽  
K. Mahesh Kumar ◽  
O. Kotresh ◽  
H. C. Devarajegowda
Keyword(s):  
Crystal Structure ◽  
Chair Conformation ◽  
Ring System ◽  
Piperidine Ring ◽  
Dihedral Angles ◽  
Maximum Deviation ◽  
Compound C ◽  
Centroid Distance ◽  
The Mean ◽  
Chromene Ring

In the title compound, C17H19NO2S2, the 2H-chromene ring system is nearly planar, with a maximum deviation of 0.0383 (28) Å, and the piperidine ring adopts a chair conformation. The 2H-chromene ring makes dihedral angles of 32.89 (16) and 67.33 (8)°, respectively, with the mean planes of the piperidine ring and the carbodithioate group. In the crystal, C—H...O and weak C—H...S hydrogen bonds link the molecules into chains along [001]. The crystal structure also features C—H...π and π–π interactions, with a centroid–centroid distance of 3.7097 (17) Å.

Measuring the Perceptual Similarity of Pitch Contours

1998 ◽  
Vol 41 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Dik J. Hermes
Keyword(s):  
Foreign Language ◽  
Correlation Coefficient ◽  
Visual Display ◽  
Companion Paper ◽  
Pitch Contour ◽  
Maximum Deviation ◽  
Perceptual Similarity ◽  
Pitch Contours ◽  
The Mean ◽  
Display Systems

It has been shown that visual display systems of intonation can be employed beneficially in teaching intonation to persons with deafness and in teaching the intonation of a foreign language. In current training situations the correctness of a reproduced pitch contour is rated either by the teacher or automatically. In the latter case an algorithm mostly estimates the maximum deviation from an example contour. In game-like exercises, for instance, the pupil has to produce a pitch contour within the displayed floor and ceiling of a "tunnel" with a preadjusted height. In an experiment described in the companion paper, phoneticians had rated the dissimilarity of two pitch contours both auditorily, by listening to two resynthesized utterances, and visually, by looking at two pitch contours displayed on a computer screen. A test is reported in which these dissimilarity ratings were compared with automatic ratings obtained with this tunnel measure and with three other measures, the mean distance, the root-mean-square (RMS) distance, and the correlation coefficient. The most frequently used tunnel measure appeared to have the weakest correlation with the ratings by the phoneticians. In general, the automatic ratings obtained with the correlation coefficient showed the strongest correlation with the perceptual ratings. A disadvantage of this measure, however, may be that it normalizes for the range of the pitch contours. If range is important, as in intonation teaching to persons with deafness, the mean distance or the RMS distance are the best physical measures for automatic training of intonation.

scholarly journals 9-(2,4-Dinitrophenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione

2013 ◽  
Vol 69 (2) ◽  
pp. o281-o281 ◽  
Author(s):  
N. Sureshbabu ◽  
V. Sughanya
Keyword(s):  
Dihedral Angle ◽  
Title Compound ◽  
Maximum Deviation ◽  
Boat Conformation ◽  
Pyran Ring ◽  
Compound C ◽  
The Mean

In the title compound, C23H24N2O7, the central 4H-pyran ring adopts a flattened boat conformation, whereas both cyclohexenone rings adopt envelope conformations, the C atom bearing the dimethyl substituent being the flap atom in each case. The mean and maximum deviation of the pyran ring are 0.0379 (4) and 0.0605 (3) Å. The mean plane of the pyran ring and the dinitrobenzene ring make a dihedral angle of 85.88 (2)°.

scholarly journals 2-Amino-4-(4-chlorophenyl)-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile propan-2-one monosolvate

2012 ◽  
Vol 68 (6) ◽  
pp. o1965-o1966 ◽  
Author(s):  
Shaaban K. Mohamed ◽  
Mehmet Akkurt ◽  
Muhammad N. Tahir ◽  
Antar A. Abdelhamid ◽  
Mustafa R. Albayati
Keyword(s):  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Layer Structure ◽  
Maximum Deviation ◽  
Pyran Ring ◽  
Compound C ◽  
Cyclohexene Ring ◽  
The Mean ◽  
Graph Set ◽  
Puckering Parameters

In the title compound, C18H17ClN2O2·C3H6O, the 4H-pyran ring is nearly planar [maximum deviation = −0.108 (1) Å] and the cyclohexene ring is puckered [puckering parameters Q T = 0.4596 (17) Å, θ = 55.9 (2)° and φ = 226.5 (3)°]. The 4H-pyran ring is approximately perpendicular to the benzene ring [dihedral angle = 84.35 (7)°] and is almost coplanar with the mean plane of the cyclohexene ring [dihedral angle = 8.64 (7)°]. In the crystal, inversion-related main molecules are linked into dimers by pairs of N—H...N hydrogen bonds, generating an R 2 2(12) graph-set motif. These dimers are further connected by N—H...O and C—H...N hydrogen bonds, forming a layer structure extending parallel to the (011) plane. In addition, the molecules within the layers interact with each other via C—H...π interactions.

scholarly journals 2-(4-Bromophenyl)-2-oxoethyl anthracene-9-carboxylate

2012 ◽  
Vol 68 (6) ◽  
pp. o1876-o1876 ◽  
Author(s):  
Hoong-Kun Fun ◽  
Safra Izuani Jama Asik ◽  
B. Garudachari ◽  
Arun M. Isloor ◽  
M. N Satyanarayan
Keyword(s):  
Hydrogen Bond ◽  
Ring System ◽  
Maximum Deviation ◽  
Stacking Interactions ◽  
Two Dimensional ◽  
Compound C ◽  
Dimensional Network ◽  
Benzene Rings ◽  
The Mean ◽  
Ring Motif

In the title compound, C23H15BrO3, the anthracene ring system is essentially planar [maximum deviation = 0.29 (2) Å] and makes a dihedral angle of 5.74 (8)° with the mean plane of the bromo-substituted benzene ring. An intramolecular C—H...O hydrogen bond generates an S(9) ring motif. In the crystal, molecules are linked by C—H...O interactions, forming a two-dimensional network parallel to the ac plane. π–π stacking interactions are observed between benzene rings [centroid–centroid distances = 3.5949 (14) and 3.5960 (13) Å].

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