scholarly journals CFD Study of Diffuse Ceiling Ventilation through Perforated Ceiling Panels

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1995 ◽  
Author(s):  
Alessandro Nocente ◽  
Tufan Arslan ◽  
Steinar Grynning ◽  
Francesco Goia
Keyword(s):  
System Performance ◽  
Three Dimensional ◽  
General System ◽  
Performance Comparison ◽  
Air Distribution ◽  
Velocity Magnitude ◽  
Numerical Studies ◽  
Negative Effect ◽  
Office Rooms ◽  
Dimensional Domain

Diffuse Ceiling Ventilation (DCV) is a promising concept to address internal air quality and thermal comfort requirements in contemporary buildings. Sound-absorbing perforated ceiling panels are common in office rooms and can be used as air diffusers without modifications. The optimization of such systems is not a trivial procedure, and numerical simulation can represent an important tool to carry out this task. Today, most of the numerical studies on DCV are performed using porous medium models and focus on the general system performance rather than on the optimization of the diffuser design. In previous studies, a CFD model was used to optimize the size and distribution of the ceiling perforation. In the study presented in this paper, the results of simulations conducted on a full-scale three-dimensional domain and the performance comparison between a continuous and non-continuous perforation distribution are given. The results show that the non-continuous diffuser design does not disturb the internal comfort and does not introduce a negative effect in the system performance. The different configurations lead to a different air distribution in the room, but in both cases, the velocity magnitude is always well below values leading to draft discomfort.

Evaluation of the Wave-Resistance Green Function: Part 1—The Double Integral

1987 ◽  
Vol 31 (02) ◽  
pp. 79-90
Author(s):  
J. N. Newman
Keyword(s):  
Asymptotic Behavior ◽  
Three Dimensional ◽  
Steady Motion ◽  
Wave Resistance ◽  
Integral Representations ◽  
Far Field ◽  
Double Integral ◽  
Numerical Studies ◽  
Single Integral ◽  
Dimensional Domain

Analytical and numerical studies are made of the source potential for steady motion beneath a free surface. Various alternative integral representations are reviewed, and attention is focused on the component which usually is expressed as a double integral. A particular form is selected for numerical applications, where the double integral represents a symmetrical nonradiating disturbance, and the far-field waves are accounted for separately in the complementary single integral. Systematic expansions are derived for the singularity of the double integral at the origin, and for its asymptotic behavior far from the origin. Guided by these expansions, numerical approximations of the double integral are derived in terms of three-dimensional polynomials, which greatly facilitate the computation of the double integral. Tables of the coefficients in these approximations are presented, permitting the double integral to be evaluated throughout the three-dimensional domain with an accuracy of five to six decimal places. Greater accuracy can be achieved by using extended tables of the same coefficients. Algorithms for evaluating the Chebyshev polynomial approximations and a description of the computational methods used to derive the coefficients are included in the Appendices.

scholarly journals Interactions Crucial for Three-Dimensional Domain Swapping in the HP-RNase Variant PM8

2011 ◽  
Vol 101 (2) ◽  
pp. 459-467 ◽  
Author(s):  
Pere Tubert ◽  
Douglas V. Laurents ◽  
Marc Ribó ◽  
Marta Bruix ◽  
Maria Vilanova ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Domain Swapping ◽  
Dimensional Domain

scholarly journals Application of the erosion algorithm in modeling of structures behavior under impulse loads

2019 ◽  
Vol 221 ◽  
pp. 01003
Author(s):  
Pavel Radchenko ◽  
Stanislav Batuev ◽  
Andrey Radchenko
Keyword(s):  
Finite Element ◽  
High Velocity ◽  
Three Dimensional ◽  
Computer Software ◽  
Dynamic Loads ◽  
Complex Structures ◽  
Numerical Studies ◽  
Contact Surfaces ◽  
Fracture Of Materials ◽  
Solid Bodies

The paper presents results of applying approach to simulation of contact surfaces fracture under high velocity interaction of solid bodies. The algorithm of erosion -the algorithm of elements removing, of new surface building and of mass distribution after elements fracture at contact boundaries is consider. The results of coordinated experimental and numerical studies of fracture of materials under impact are given. Authors own finite element computer software program EFES, allowing to simulate a three-dimensional setting behavior of complex structures under dynamic loads, has been used for the calculations.

scholarly journals Formation, structure, and dissociation of the ribonuclease S three-dimensional domain-swapped dimer. VOLUME 281 (2006) PAGES 9400-9406

2007 ◽  
Vol 282 (17) ◽  
pp. 13139
Author(s):  
Jorge P. López-Alonso ◽  
Marta Bruix ◽  
Josep Font ◽  
Marc Ribó ◽  
María Vilanova ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dimensional Domain

An Efficient Sparse Finite Element Solver for the Radiative Transfer Equation

2009 ◽  
Author(s):  
Gisela Widmer
Keyword(s):  
Linear System ◽  
Radiative Transfer ◽  
Transfer Equation ◽  
Degrees Of Freedom ◽  
Radiative Transfer Equation ◽  
Three Dimensional ◽  
Discrete Ordinates ◽  
Five Dimensions ◽  
Computational Costs ◽  
Dimensional Domain

The stationary monochromatic radiative transfer equation (RTE) is posed in five dimensions, with the intensity depending on both a position in a three-dimensional domain as well as a direction. For non-scattering radiative transfer, sparse finite elements [1, 2] have been shown to be an efficient discretization strategy if the intensity function is sufficiently smooth. Compared to the discrete ordinates method, they make it possible to significantly reduce the number of degrees of freedom N in the discretization with almost no loss of accuracy. However, using a direct solver to solve the resulting linear system requires O(N3) operations. In this paper, an efficient solver based on the conjugate gradient method (CG) with a subspace correction preconditioner is presented. Numerical experiments show that the linear system can be solved at computational costs that are nearly proportional to the number of degrees of freedom N in the discretization.

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