A 6th order staggered compact finite difference method for the incompressible Navier–Stokes and scalar transport equations

Boersma, Bendiks Jan

doi:10.1016/j.jcp.2011.03.014

Cited by 56 publications

(40 citation statements)

References 18 publications

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“…The heat is removed from the two isothermal walls, resulting in averaged temperature and property profiles that are symmetric about the channel center with the maximum average temperature in the middle of the channel. The DNS code discretizes the spatial derivatives in the wall-normal direction using a sixth-order staggered compact finite difference scheme [26,27]. The derivatives in the homogeneous spanwise and streamwise directions are computed using a Fourier expansion with periodic boundary conditions.…”

Section: Simulation Detailsmentioning

confidence: 99%

Scalar statistics in variable property turbulent channel flows

2017

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Direct numerical simulation of fully developed, internally heated channel flows with isothermal walls is performed using the low-Mach-number approximation of Navier-Stokes equation to investigate the influence of temperature-dependent properties on turbulent scalar statistics. Different constitutive relations for density ρ, viscosity μ, and thermal conductivity λ as a function of temperature are prescribed in order to characterize the turbulent scalar statistics. It is shown that the dominant effect caused by property variations on scalar statistics can be parameterized by two nondimensional parameters, namely the semilocal Reynolds number Re τ ≡ Re τ √ (ρ/ρ w )/(μ/μ w ) (the bar and subscript w denote Reynolds averaging and wall value respectively, while Re τ is the friction Reynolds number based on wall values), and the local Prandtl number Pr = Pr w (μ/μ w )/(λ/λ w ) (Pr w is the molecular Prandtl number based on wall values). Near-wall gradients in Re τ modulate the turbulent heat flux generation mechanism because of structural changes in turbulence. However, the influence of these modulations on the inner scaling of turbulent heat conductivity normalized by local mean viscosity is shown to be weak. Using this observation, a temperature transformation is derived that is invariant of Re τ variations and only exhibits a Pr -dependent shift.

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Section: Simulation Detailsmentioning

confidence: 99%

Scalar statistics in variable property turbulent channel flows

2017

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“…By using the projection method the velocity u* given by N-S conservation momentum Equation (5) is included in the following (Poisson) [25] equation: ∇¨u˚" ∆t ∇¨p∇pq (9) in order to estimate the water pressure. In Equation (9) u* is the intermediate velocity whose value is based on the viscous stress.…”

Section: Advancement Of Saline Front In a Fracture Using N-smentioning

confidence: 99%

A New Method to Infer Advancement of Saline Front in Coastal Groundwater Systems by 3D: The Case of Bari (Southern Italy) Fractured Aquifer

Masciopinto¹,

Palmiotta²

2016

Computation

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Abstract:A new method to study 3D saline front advancement in coastal fractured aquifers has been presented. Field groundwater salinity was measured in boreholes of the Bari (Southern Italy) coastal aquifer with depth below water table. Then, the Ghyben-Herzberg freshwater/saltwater (50%) sharp interface and saline front position were determined by model simulations of the freshwater flow in groundwater. Afterward, the best-fit procedure between groundwater salinity measurements, at assigned water depth of 1.0 m in boreholes, and distances of each borehole from the modelled freshwater/saltwater saline front was used to convert each position (x, y) in groundwater to the water salinity concentration at depth of 1.0 m. Moreover, a second best-fit procedure was applied to the salinity measurements in boreholes with depth z. These results provided a grid file (x, y, z, salinity) suitable for plotting the actual Bari aquifer salinity by 3D maps. Subsequently, in order to assess effects of pumping on the saltwater-freshwater transition zone in the coastal aquifer, the Navier-Stokes (N-S) equations were applied to study transient density-driven flow and salt mass transport into freshwater of a single fracture. The rate of seawater/freshwater interface advancement given by the N-S solution was used to define the progression of saline front in Bari groundwater, starting from the actual salinity 3D map. The impact of pumping of 335 L¨s´1 during the transition period of 112.8 days was easily highlighted on 3D salinity maps of Bari aquifer.

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“…The study uses the Box-Behnken design because it has fewer design points and is less expensive to run than central composite designs with the same number of factors. The Box-Behnken design was used to optimize the experiment to judge the effects of important parameters by using the response surface method (Abou-El-Hossein, Kadirgama, Hamdi, & Benyounis, 2007;Boersma, 2011;Rahman, Khan, Kadirgama, Noor, & Bakar, 2010a, 2010bZhao, Wu, & Wang, 2006). Three levels of cutting parameters were selected to investigate the machinability of this alloy, as shown in Table 1.…”

Section: Design Of Experimentsmentioning

confidence: 99%

Experimental Study on Surface Integrity in End Milling of Hastelloy C-2000 Superalloy

Razak¹,

Rahman²,

Kadirgama³

2014

Int J Automot Mech Eng

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This paper presents an experimental study of surface integrity in end milling of Hastelloy C-2000. The experiment was carried out using two different cutting inserts under wet conditions -namely physical vapor deposition coated carbide with TiAlN and uncoated carbide. Design of experiment was implemented with a Box-Behnken design. The surface integrity of the workpiece was analyzed through scanning electron microscopy (SEM) and chemical element changes were inspected by an energy dispersive X-ray (EDX) test. The surface integrity of Hastelloy C-2000 was better when machining with coated carbide compared to uncoated carbide cutting inserts, mainly because the coating layer of coated carbide acted as a protecting layer to the cutting tool insert. Surface defects such as feed marks, surface tearing, plucking, cracking and adhered chips were found during the machining process. The chemical element changes happened due to the adhesion and diffusion mechanisms which were identified using SEM and EDX.

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A 6th order staggered compact finite difference method for the incompressible Navier–Stokes and scalar transport equations

Cited by 56 publications

References 18 publications

Scalar statistics in variable property turbulent channel flows

Scalar statistics in variable property turbulent channel flows

A New Method to Infer Advancement of Saline Front in Coastal Groundwater Systems by 3D: The Case of Bari (Southern Italy) Fractured Aquifer

Experimental Study on Surface Integrity in End Milling of Hastelloy C-2000 Superalloy

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