CFD Challenge: Solutions Using the Mesher, Harpoon, and the Finite Volume Solver, Fluent

2012 ◽  
Author(s):  
Neil W. Bressloff ◽  
Ahsan T. Hameed
Keyword(s):  
Cardiovascular Disease ◽  
General Hospital ◽  
Finite Volume ◽  
Ansys Fluent ◽  
Vascular Stents ◽  
Southampton General Hospital

The Bressloff group has focused on cardiovascular disease and its treatment for the last ten years. Possessing close ties with Southampton General Hospital, much of the work has sought understanding and/or solutions to clinically relevant problems, including the design of vascular stents. For the CFD Challenge, preliminary verification studies were performed by Masters student Ahsan Hameed using a fast hex-dominant mesher, Harpoon (Sharc Ltd) and V12.1.4 of the ANSYS Fluent solver (ANSYS, Inc.).

Effect of Slit Inclusions in Drag Reduction of Flow over Cylinders

2016 ◽  
Vol 846 ◽  
pp. 18-22
Author(s):  
Rohit Bhattacharya ◽  
Abouzar Moshfegh ◽  
Ahmad Jabbarzadeh
Keyword(s):  
Fluid Flow ◽  
Drag Reduction ◽  
Drag Coefficient ◽  
Finite Volume ◽  
Lattice Boltzmann ◽  
Circular Cross Section ◽  
Finite Volume Methods ◽  
Turbulent Regime ◽  
Ansys Fluent ◽  
Comparison Of The Results

The flow over bluff bodies is separated compared to the flow over streamlined bodies. The investigation of the fluid flow over a cylinder with a streamwise slit has received little attention in the past, however there is some experimental evidence that show for turbulent regime it reduces the drag coefficient. This work helps in understanding the fluid flow over such cylinders in the laminar regime. As the width of the slit increases the drag coefficient keeps on reducing resulting in a narrower wake as compared to what is expected for flow over a cylinder. In this work we have used two different approaches in modelling a 2D flow for Re=10 to compare the results for CFD using finite volume method (ANSYS FLUENTTM) and Lattice Boltzmann methods. In all cases cylinders of circular cross section have been considered while slit width changing from 10% to 40% of the cylinder diameter. . It will be shown that drag coefficient decreases as the slit ratio increases. The effect of slit size on drag reduction is studied and discussed in detail in the paper. We have also made comparison of the results obtained from Lattice Boltzmann and finite volume methods.

Aerodynamic study of single corrugated variable-camber morphing aerofoil concept

2021 ◽  
pp. 1-29
Author(s):  
K. Dhileep ◽  
D. Kumar ◽  
P.N. Gautham Vigneswar ◽  
P. Soni ◽  
S. Ghosh ◽  
...  
Keyword(s):  
Finite Volume ◽  
Interpolation Method ◽  
Beam Theory ◽  
Small Deformation ◽  
Aerodynamic Characteristics ◽  
Ansys Fluent ◽  
Aerodynamic Efficiency ◽  
Finite Element Software ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract Camber morphing is an effective way to control the lift generated by any aerofoil and potentially improve the range (as measured by the lift-to-drag ratio) and endurance (as measured by $C_l^{3/2}/C_d$ ). This can be especially useful for fixed-wing Unmanned Aerial Vehicles (UAVs) undergoing different flying manoeuvres and flight phases. This work investigates the aerodynamic characteristics of the NACA0012 aerofoil morphed using a Single Corrugated Variable-Camber (SCVC) morphing approach. Structural analysis and morphed shapes are obtained based on small-deformation beam theory using chain calculations and validated using finite-element software. The aerofoil is then reconstructed from the camber line using a Radial Basis Function (RBF)-based interpolation method (J.H.S. Fincham and M.I. Friswell, “Aerodynamic optimisation of a camber morphing aerofoil,” Aerosp. Sci. Technol., 2015). The aerodynamic analysis is done by employing two different finite-volume solvers (OpenFOAM and ANSYS-Fluent) and a panel method code (XFoil). Results reveal that the aerodynamic coefficients predicted by the two finite-volume solvers using a fully turbulent flow assumption are similar but differ from those predicted by XFoil. The aerodynamic efficiency and endurance factor of morphed aerofoils indicate that morphing is beneficial at moderate to high lift requirements. Further, the optimal morphing angle increases with an increase in the required lift. Finally, it is observed for a fixed angle-of-attack that an optimum morphing angle exists for which the aerodynamic efficiency becomes maximum.

scholarly journals The workload of stroke thrombolysis: A prospective study in a district general hospital setting

2011 ◽  
Vol 10 (1) ◽  
pp. 10-12
Author(s):  
Seán J Slaght ◽  
◽  
Nic U Weir ◽  
Joanna K Lovett ◽  
◽  
...  
Keyword(s):  
Prospective Study ◽  
General Hospital ◽  
Hospital Setting ◽  
District General Hospital ◽  
Service Planning ◽  
Stroke Severity ◽  
Southampton General Hospital ◽  
Stroke Thrombolysis ◽  
Few Data ◽  
A Prospective Study

Many hospitals are still setting up acute stroke thrombolysis services, often delayed by fears over workload. However, there are few data on how many patients require urgent assessment before one is treated. We prospectively studied all referrals to the 24-hour stroke thrombolysis service, February 2009 – January 2010, in Southampton General Hospital. 128 patients were referred to the thrombolysis team and 20 received thrombolysis. The most common reasons for treatment exclusion were: stroke severity (37%), time from onset (26%) or CT findings (15%). Approximately six patients required urgent assessment by the thrombolysis team for every one treated. These data are crucial to inform service planning.

Photofluorographic Detection of Cardiovascular Disease in a General Hospital

1954 ◽  
Vol 251 (23) ◽  
pp. 934-937 ◽  
Author(s):  
Harold D. Batt ◽  
John M. Allen ◽  
Frederick H. Treder ◽  
Robert Shapiro
Keyword(s):  
Cardiovascular Disease ◽  
General Hospital

A Non-Local Convective Flux Limiter for Upwind-Biased Finite Volume Simulations

2010 ◽  
Author(s):  
Nicole M. W. Poe ◽  
D. Keith Walters
Keyword(s):  
Finite Volume ◽  
Finite Volume Methods ◽  
Second Order ◽  
Numerical Dissipation ◽  
Ansys Fluent ◽  
First Order ◽  
Low Dissipation ◽  
Solution Convergence ◽  
Improve Accuracy ◽  
Non Local

Finite volume methods on structured and unstructured meshes often utilize second-order, upwind-biased linear reconstruction schemes to approximate the convective terms, in an attempt to improve accuracy over first-order methods. Limiters are employed to reduce the inherent variable over- and under-shoot of these schemes; however, they also can significantly increase the numerical dissipation of a solution. This paper presents a novel non-local, non-monotonic (NLNM) limiter developed by enforcing cell minima and maxima on dependent variable values projected to cell faces. The minimum and maximum values for a cell are determined primarily through the recursive reference to the minimum and maximum values of its upwind neighbors. The new limiter is implemented using the User Defined Function capability available in the commercial CFD solver Ansys FLUENT. Various simple test cases are presented which exhibit the NLNM limiter’s ability to eliminate non-physical oscillations while maintaining relatively low dissipation of the solution. Results from the new limiter are compared with those from other limited and unlimited second-order upwind (SOU) and first-order upwind (FOU) schemes. For the cases examined in the study, the NLNM limiter was found to improve accuracy without significantly increasing solution convergence rate.

CFD Challenge: Solutions Using the Commercial Finite Volume Solver, Fluent

2012 ◽  
Author(s):  
Hardeep S. Kalsi ◽  
Quan Long
Keyword(s):  
Finite Volume ◽  
Aerospace Engineering ◽  
Ansys Fluent

Mr. Kalsi is currently reading 3rd year Aerospace Engineering at Brunei University, London, this CFD challenge was undertaken as a final year dissertation project under the supervision of Dr. Quan Long at the Brunel Institute for Bioengineering (BIB). Simulations were carried out using the finite volume solver package ANSYS Fluent through the educational license available at Brunel University.

A Low-Dissipation Optimization-Based Gradient Reconstruction (OGRE) Scheme for Finite Volume Simulations

2011 ◽  
Author(s):  
Nicole M. W. Poe ◽  
D. Keith Walters
Keyword(s):  
Objective Function ◽  
Finite Volume ◽  
Finite Volume Methods ◽  
Second Order ◽  
Ansys Fluent ◽  
Variable Field ◽  
Gradient Reconstruction ◽  
Low Dissipation ◽  
Upwind Discretization ◽  
Definition Of

Finite volume methods employing second-order gradient reconstruction schemes are often utilized to computationally solve the governing equations of transport. These reconstruction schemes, while not as dissipative as first-order schemes, frequently produce either dispersive or oscillatory solutions, especially in regions of discontinuities, and/or unsatisfactory levels of dissipation in smooth regions of the variable field. A novel gradient reconstruction scheme is presented in this work which shows significant improvement over traditional second-order schemes. This Optimization-based Gradient REconstruction (OGRE) scheme works to minimize an objective function based on the mismatch between local reconstructions at midpoints between cell stencil neighbors, i.e. the degree to which the projected values of a dependent variable and its gradients in a given cell differ from each of these values in neighbor cells. An adjustable weighting parameter is included in the definition of the objective function that allows the scheme to be tuned towards greater accuracy or greater stability. This scheme is implemented using the User Defined Function capability available in the commercially available CFD solver, Ansys FLUENT. Various test cases are presented that demonstrate the ability of the new method to calculate superior predictions of both a scalar transported variable and its gradients. These cases include calculation of a discontinuous variable field, several sinusoidal variable fields and a non-uniform velocity field. Results for each case are determined on both structured and unstructured meshes, and the scheme is compared with existing standard first- and second-order upwind discretization methods.

Finite Volume Particle Method for Incompressible Flows

2014 ◽  
Vol 656 ◽  
pp. 72-80
Author(s):  
Sterian Danaila ◽  
Delia Teleaga ◽  
Luiza Zavalan
Keyword(s):  
Finite Volume ◽  
Meshless Method ◽  
Incompressible Flows ◽  
Particle Method ◽  
Finite Volume Methods ◽  
Particle Methods ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Manufactured Solutions ◽  
Method Of Manufactured Solutions

This paper presents an application of the Finite Volume Particle Method to incompressible flows. The two-dimensional incompressible Navier-Stokes solver is based on Chorin’s projection method with finite volume particle discretization. The Finite Volume Particle Method is a meshless method for fluid dynamics which unifies advantages of particle methods and finite volume methods in one scheme. The method of manufactured solutions is used to examine the global discretization error and finally a comparison between finite volume particle method simulations of an incompressible flow around a fixed circular cylinder and the numerical simulations with the CFD code ANSYS FLUENT 14.0 is presented.

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