A Eulerian Method for Water Droplet Impingement by Means of an Immersed Boundary Technique

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Francesco Capizzano ◽  
Emiliano Iuliano
Keyword(s):  
Water Droplet ◽  
Numerical Solutions ◽  
Experimental Testing ◽  
Three Dimensional ◽  
Immersed Boundary ◽  
Test Cases ◽  
Ice Accretion ◽  
Droplet Impingement ◽  
Protection Systems ◽  
Numerical Approaches

The estimation of water droplet impingement is the first step toward a complete ice accretion assessment. Numerical approaches are usually implied to support the experimental testing and to provide fast responses when designing ice protection systems. Basically, two different numerical methodologies can be found in literature: Lagrangian and Eulerian. The present paper describes the design and development of a tool based on a Eulerian equation set solved on Cartesian meshes by using an immersed boundary (IB) technique. The tool aims at computing the evolution of a droplet cloud and the impingement characteristics onto the exposed surfaces of an aircraft. The robustness of the methodology and the accuracy of the approach are discussed. The method is applying to classical two- and three-dimensional test cases for which experimental data are available in literature. The results are compared with both experiments and body-fitted numerical solutions.

An Eulerian Method for Water Droplet Impingement by Means of an Immersed Boundary Technique

2012 ◽  
Author(s):  
F. Capizzano ◽  
E. Iuliano
Keyword(s):  
Water Droplet ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Immersed Boundary ◽  
Test Cases ◽  
Simulation Tool ◽  
Ice Accretion ◽  
Droplet Impingement ◽  
Eulerian Methods ◽  
Numerical Approaches

The estimation of water droplet impingement is the first step for a complete ice-accretion assessment. Basically two different numerical approaches can be found in literature: the Lagrangian and the Eulerian methods. The present paper describes the design and development of a water impingement simulation tool based on Eulerian droplet equations solved on Cartesian meshes by using an immersed boundary (IB) technique. The robustness of the methodology and the accuracy of the approach are discussed. The method is applying to classical two- and three-dimensional test-cases for which experimental data are available in literature. The results will be discussed by comparing with experimental and body-fitted numerical solutions.

A Numerical Study of Droplet Impingement for In-Flight Ice Accretion Prediction

2016 ◽  
Author(s):  
Hao Zhang ◽  
Chihyung Wen ◽  
Junwei Su
Keyword(s):  
Collection Efficiency ◽  
Numerical Study ◽  
Three Dimensional ◽  
Ice Accretion ◽  
Eulerian Model ◽  
Droplet Impingement ◽  
Basic Module ◽  
Wide Range ◽  
Subsonic Regime ◽  
Finite Volume Approach

Droplet impingement is the basic module in both ice accretion and anti-icing numerical calculation. A three dimensional finite volume approach with the capacity of modeling the in-flight droplet impingement on a wide range of subsonic regime is therefore established in this research, using OpenFOAM®. The Eulerian model is applied to estimate the droplet flow field with the same computational grid sets as those of the air flow calculation. The roughness effect caused by ice accretion is considered in the wall function modeling. Thus, the collection efficiency could be investigated for further icing numerical simulations. This approach is validated on both cylinder and sphere benchmark cases. The results are compared with the corresponding experimental and LEWICE (LEWis ICE accretion program) simulation data.

A three-dimensional immersed boundary method based on an algebraic forcing-point-searching scheme for water impact problems

2021 ◽  
Vol 233 ◽  
pp. 109189
Author(s):  
Bin Yan ◽  
Wei Bai ◽  
Sheng-Chao Jiang ◽  
Peiwen Cong ◽  
Dezhi Ning ◽  
...  
Keyword(s):  
Immersed Boundary Method ◽  
Three Dimensional ◽  
Immersed Boundary ◽  
Water Impact ◽  
Boundary Method ◽  
Impact Problems

Numerical solutions for strain-softening surrounding rock under three-dimensional principal stress condition

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sheng Yu-ming ◽  
Li Chao ◽  
Xia Ming-yao ◽  
Zou Jin-feng
Keyword(s):  
Finite Element ◽  
Principal Stress ◽  
Stress Condition ◽  
Strain Softening ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Strength Criterion ◽  
Surrounding Rock ◽  
Flow Rule ◽  
Finite Element Software

Abstract In this study, elastoplastic model for the surrounding rock of axisymmetric circular tunnel is investigated under three-dimensional (3D) principal stress states. Novel numerical solutions for strain-softening surrounding rock were first proposed based on the modified 3D Hoek–Brown criterion and the associated flow rule. Under a 3D axisymmetric coordinate system, the distributions for stresses and displacement can be effectively determined on the basis of the redeveloped stress increment approach. The modified 3D Hoek–Brown strength criterion is also embedded into finite element software to characterize the yielding state of surrounding rock based on the modified yield surface and stress renewal algorithm. The Euler implicit constitutive integral algorithm and the consistent tangent stiffness matrix are reconstructed in terms of the 3D Hoek–Brown strength criterion. Therefore, the numerical solutions and finite element method (FEM) models for the deep buried tunnel under 3D principal stress condition are presented, so that the stability analysis of surrounding rock can be conducted in a direct and convenient way. The reliability of the proposed solutions was verified by comparison of the principal stresses obtained by the developed numerical approach and FEM model. From a practical point of view, the proposed approach can also be applied for the determination of ground response curve of the tunnel, which shows a satisfying accuracy compared with the measuring data.

scholarly journals Automatized Evaluation of Students’ CAD Models

2021 ◽  
Vol 11 (4) ◽  
pp. 145
Author(s):  
Nenad Bojcetic ◽  
Filip Valjak ◽  
Dragan Zezelj ◽  
Tomislav Martinec
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Computer Application ◽  
Test Cases ◽  
Cad Model ◽  
Computer Solution ◽  
3D Cad ◽  
Computer Aided ◽  
Cad Models ◽  
Aided Design

The article describes an attempt to address the automatized evaluation of student three-dimensional (3D) computer-aided design (CAD) models. The driving idea was conceptualized under the restraints of the COVID pandemic, driven by the problem of evaluating a large number of student 3D CAD models. The described computer solution can be implemented using any CAD computer application that supports customization. Test cases showed that the proposed solution was valid and could be used to evaluate many students’ 3D CAD models. The computer solution can also be used to help students to better understand how to create a 3D CAD model, thereby complying with the requirements of particular teachers.

Three-Dimensional Vibration Analysis of Twisted Cylinder With Sectorial Cross Section

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
D. Zhou ◽  
S. H. Lo
Keyword(s):  
Cross Section ◽  
Chebyshev Polynomial ◽  
Numerical Solutions ◽  
Twist Angle ◽  
Ritz Method ◽  
Three Dimensional ◽  
Cylindrical Domain ◽  
Linear Elasticity Theory ◽  
Boundary Functions ◽  
Polynomial Series

The three-dimensional (3D) free vibration of twisted cylinders with sectorial cross section or a radial crack through the height of the cylinder is studied by means of the Chebyshev–Ritz method. The analysis is based on the three-dimensional small strain linear elasticity theory. A simple coordinate transformation is applied to map the twisted cylindrical domain into a normal cylindrical domain. The product of a triplicate Chebyshev polynomial series along with properly defined boundary functions is selected as the admissible functions. An eigenvalue matrix equation can be conveniently derived through a minimization process by the Rayleigh–Ritz method. The boundary functions are devised in such a way that the geometric boundary conditions of the cylinder are automatically satisfied. The excellent property of Chebyshev polynomial series ensures robustness and rapid convergence of the numerical computations. The present study provides a full vibration spectrum for thick twisted cylinders with sectorial cross section, which could not be determined by 1D or 2D models. Highly accurate results presented for the first time are systematically produced, which can serve as a benchmark to calibrate other numerical solutions for twisted cylinders with sectorial cross section. The effects of height-to-radius ratio and twist angle on frequency parameters of cylinders with different subtended angles in the sectorial cross section are discussed in detail.

Water droplet impingement on airfoils and aircraft engine inlets foricing analysis

1991 ◽  
Vol 28 (3) ◽  
pp. 165-174 ◽  
Author(s):  
Michael Papadakis ◽  
R. Elangovan ◽  
George A. Freund ◽  
Marlin D. Breer
Keyword(s):  
Water Droplet ◽  
Aircraft Engine ◽  
Droplet Impingement
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