The purpose of this paper is to propose an adaptive refinement strategy based on a posteriori error estimate for the efficient simulation of free surface flows using discrete…
Abstract
Purpose
The purpose of this paper is to propose an adaptive refinement strategy based on a posteriori error estimate for the efficient simulation of free surface flows using discrete least squares meshless (DLSM) method.
Design/methodology/approach
A pressure projection method is employed to discretize the governing equations of mass and momentum conservation in a Lagrangian form. The semi‐discretized equations are then discretized in space using the DLSM method, in which the sum of squared residual of the governing equations and their boundary conditions are minimized with respect to the unknown nodal parameters.
Findings
Since the position of the free surface is of great significant in free surface problems, a posteriori error estimator which automatically associates higher error to the nodes near the free surface is proposed and used along with a node moving refinement strategy to simulate the free surface problems more efficiently. To test the ability and efficiency of the proposed adaptive simulation method, two test problems, namely dam break and evolution of a water bubble, are solved and the results are presented and compared to those of analytical and experimental results.
Originality/value
Error estimate and adaptive refinement have been mostly used in confined and steady‐state flow. Here in this paper, a new attempt has been made to use these concepts in moving boundary problem.
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Gholamreza Shobeyri and Mohammad Yourdkhani
The purpose of this paper is to develop an efficient and accurate mesh-less method to simulate free flows with continuous deformation in boundary positions.
Abstract
Purpose
The purpose of this paper is to develop an efficient and accurate mesh-less method to simulate free flows with continuous deformation in boundary positions.
Design/methodology/approach
A two-step pressure projection method in a Lagrangian form is used to solve the governing equations of mass and momentum conservation. In the first step, velocity field is calculated in which incompressibility is not enforced. In the second step, a pressure Poisson equation is applied to satisfy incompressibility conditions. The numerical proposed method is used for spatial discretization of the governing equations. Three benchmark-free surface problems, namely, dam break, solitary wave propagation and evolution of an elliptical bubble with available experimental results and analytical solutions, are used to test the accuracy of the proposed method. The results prove the accuracy of the method in simulating free surface problems.
Findings
The Voronoi diagram instead of kernel function summation can be used to estimate the particle or nodal volume concept in particle-based (mesh-less) methods for function approximation. This idea probably works well especially for highly irregular node distributions.
Originality/value
The continuous moving least squares shape functions are applied for function approximation, and the Voronoi diagram concept is also used to estimate region influence of computational nodal points or particle volumes. Combinations of these two concepts and finite differences formulation for first derivatives gives an accurate numerical model for Laplacian operator in the proposed method.
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This chapter addresses Bangladeshi female students’ experiences of higher education in the United Kingdom through the race/gender trajectory. Research shows that although minority…
Abstract
Purpose
This chapter addresses Bangladeshi female students’ experiences of higher education in the United Kingdom through the race/gender trajectory. Research shows that although minority ethnic women invest heavily in education, they go on to face obstacles in the labour market. However, there is a strong desire to study which is evident in the increasing numbers of Bangladeshi women applying to university since 1994. The chapter draws on empirical research with women who have claimed a kind of ‘agentic autonomy’ to pursue education in the face of structural inequalities.
Design/methodology/approach
The chapter is based on research conducted with a sample of Bangladeshi women studying at or recently graduated from university. Qualitative research was carried out in the form of semi-structured interviews with 13 participants.
Findings
The study finds that Bangladeshi women are undeterred by structural inequalities in higher education and employment. Although they expect to face some difficulty finding suitable employment, they are optimistic about the future. They represent a group of women who have been able to achieve their objectives to study at degree level and show aspirations towards achieving similar objectives after graduation.
Originality/value
Bangladeshi women show agency and agentic behaviour to negotiate access to higher education institutions. This will, in the future have a knock-on effect in employment.
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Philomena Essed and Karen Carberry
The hiring of women of colour faculty is not without unwritten presuppositions. The authors are expected to tolerate racism and to draw from cultural experience in catering to…
Abstract
The hiring of women of colour faculty is not without unwritten presuppositions. The authors are expected to tolerate racism and to draw from cultural experience in catering to students of colour or when it fulfils institutional needs such as bringing ‘colour’ to all-white committees. Yet, the normative profile of university teachers demands detachment with a focus on high output in terms of students and publications. In the light of this, commitment to social justice seems to be in (certain) disagreements with mainstream interpretations of the academic profession. Women of colour professors are redefining educational leadership. This chapter addresses its effect on emotional wellbeing together with techniques and strategies to strengthen emotional resilience.
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Aisha K. Gill and Aviah Sarah Day
In May 2012, nine men from the Rochdale area of Manchester were found guilty of sexually exploiting a number of underage girls. Reporting on the trial, the media focussed on the…
Abstract
In May 2012, nine men from the Rochdale area of Manchester were found guilty of sexually exploiting a number of underage girls. Reporting on the trial, the media focussed on the fact that eight of the nine men were of Pakistani origin, while the girls were all white. It also framed similar cases in Preston, Rotherham, Derby, Shropshire, Oxford, Telford and Middlesbrough as ethnically motivated, thus creating a moral panic centred on South Asian grooming gangs preying on white girls. Despite the lack of evidence that the abuse perpetrated by some Asian men is distinct from male violence against women generally, the media focus on the grooming gang cases has constructed a narrative in which South Asian men pose a unique sexual threat to white girls. This process of ‘othering’ South Asian men in terms of abusive behaviour masks the fact that in the United Kingdom, the majority of sexual and physical abuse is perpetrated by white men; it simultaneously marginalises the sexual and domestic violence experienced by black and minority ethnic women. Indeed, the sexual abuse of South Asian women and girls is invisibilised within this binary discourse, despite growing concerns and evidence that the men who groomed the young girls in the aforementioned cases had also perpetrated domestic and sexual violence in their homes against their wives/partners. Through discourse analysis of newspaper coverage of these cases for the period 2012‒2018, this paper examines the British media's portrayal of South Asian men – particularly Pakistani men – in relation to child-grooming offences and explores the conditions under which ‘South Asian men’ have been constructed as ‘folk devils’. It also highlights the comparatively limited newspaper coverage of the abuse experiences and perspectives of Asian women and girls from the same communities to emphasise that violence against women and girls remains an ongoing problem across the nation.
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Zohreh Heydari, Gholamreza Shobeyri and Seyed Hossein Ghoreishi Najafabadi
This paper aims to examine the accuracy of several higher-order incompressible smoothed particle hydrodynamics (ISPH) Laplacian models and compared with the classic model (Shao…
Abstract
Purpose
This paper aims to examine the accuracy of several higher-order incompressible smoothed particle hydrodynamics (ISPH) Laplacian models and compared with the classic model (Shao and Lo, 2003).
Design/methodology/approach
The numerical errors in solving two-dimensional elliptic partial differential equations using the Laplacian models are investigated for regular and highly irregular node distributions over a unit square computational domain.
Findings
The numerical results show that one of the Laplacian models, which is newly developed by one of the authors (Shobeyri, 2019) can get the smallest errors for various used node distributions.
Originality/value
The newly proposed model is formulated by the hybrid of the standard ISPH Laplacian model combined with Taylor expansion and moving least squares method. The superiority of the proposed model is significant when multi-resolution irregular node distributions commonly seen in adaptive refinement strategies used to save computational cost are applied.
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Mohammad Hajiazizi and Adel Graili
The purpose of this paper is to extend the scaled boundary radial point interpolation method (SBRPIM), as a novel semi-analytical scheme, to the analysis of the steady state…
Abstract
Purpose
The purpose of this paper is to extend the scaled boundary radial point interpolation method (SBRPIM), as a novel semi-analytical scheme, to the analysis of the steady state confined seepage flows.
Design/methodology/approach
This method combines the advantages of the scaled boundary finite element method and the BRPIM. In this method, only boundary nodes are used, no fundamental solution of the problem is required, and as the shape functions constructed based on the RPIM satisfy the Kronecker delta function property, the boundary conditions of problems can be imposed accurately and easily.
Findings
Three numerical examples, including seepage flow through homogeneous and non-homogeneous soils, are analyzed in this paper. Comparing the flow net obtained by SBRPIM and other numerical methods confirms the ability of the proposed method in analyzing seepage flows. In addition, in these examples, the accuracy of the SBRPIM in modeling the velocity singularity at a sharp corner is illustrated. SBRPIM accurately models the singularity point in non-homogeneous and anisotropic soil.
Originality/value
SBRPIM method is a simple effective tool for analyzing various kinds of engineering problems. It is easy to implement for modeling the velocity singularity at a sharp corner. The proposed method accurately models the singularity point in non-homogeneous and anisotropic soil.
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Behrooz Ariannezhad, Shahram Shahrooi and Mohammad Shishesaz
1) The OE-MLPG penalty meshfree method is developed to solve cracked structure.(2) Smartening the numerical meshfree method by combining the particle swarm optimization (PSO…
Abstract
Purpose
1) The OE-MLPG penalty meshfree method is developed to solve cracked structure.(2) Smartening the numerical meshfree method by combining the particle swarm optimization (PSO) optimization algorithms and Voronoi computational geometric algorithm. (3). Selection of base functions, finding optimal penalty factor and distribution of appropriate nodal points to the accuracy of calculation in the meshless local Petrov–Galekrin (MLPG) meshless method.
Design/methodology/approach
Using appropriate shape functions and distribution of nodal points in local domains and sub-domains and choosing an approximation or interpolation method has an effective role in the application of meshless methods for the analysis of computational fracture mechanics problems, especially problems with geometric discontinuity and cracks. In this research, computational geometry technique, based on the Voronoi diagram (VD) and Delaunay triangulation and PSO algorithm, are used to distribute nodal points in the sub-domain of analysis (crack line and around it on the crack plane).
Findings
By doing this process, the problems caused by too closeness of nodal points in computationally sensitive areas that exist in general methods of nodal point distribution are also solved. Comparing the effect of the number of sentences of basic functions and their order in the definition of shape functions, performing the mono-objective PSO algorithm to find the penalty factor, the coefficient, convergence, arrangement of nodal points during the three stages of VD implementation and the accuracy of the answers found indicates, the efficiency of V-E-MLPG method with Ns = 7 and ß = 0.0037–0.0075 to estimation of 3D-stress intensity factors (3D-SIFs) in computational fracture mechanics.
Originality/value
The present manuscript is a continuation of the studies (Ref. [33]) carried out by the authors, about; feasibility assessment, improvement and solution of challenges, introduction of more capacities and capabilities of the numerical MLPG method have been used. In order to validate the modeling and accuracy of calculations, the results have been compared with the findings of reference article [34] and [35].
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Omid Amiri, Mahmoud Rahimi, Amir Ayazi and Garshasb Khazaeni
Nowadays, engineering, procurement and construction (EPC) contracts are being widely used to perform industrial and infrastructure projects because of several reasons like high…
Abstract
Purpose
Nowadays, engineering, procurement and construction (EPC) contracts are being widely used to perform industrial and infrastructure projects because of several reasons like high speed of implementation. However, these contracts are always accompanied by high risks and uncertainties. Thus, selection of the right EPC contractor has significant importance. This paper aims to present a fuzzy multi-criteria decision-making (MCDM) model for EPC contractor prequalification.
Design/methodology/approach
First, the EPC contractor prequalification criteria are defined by using literature review and interviewing experts. Second, the weights of criteria are determined by interviewing experts. Then, each EPC contractor is evaluated in each criterion. Finally, fuzzy weighted average (FWA) approach is employed to select the right contractor among potential EPC contractors.
Findings
The proposed model is prepared as an applicable model for clients to select the right EPC contractors among contractors who want to conduct the project.
Originality/value
As a lack of applicable model does exist to assign the prequalification of EPC contractors, this study is one of the first research studies which proposed a fuzzy MCDM model for evaluation of EPC contractors. To cope with the uncertainty of the prequalification problem, fuzzy logic has been used. Using fuzzy sets leads to reaching more reliable results. Also, a real case study is provided to explain the proposed model.