Coupled Multibody-Fluid Dynamics Simulation of Flapping Wings

2013 ◽  
Author(s):  
Mattia Alioli ◽  
Marco Morandini ◽  
Pierangelo Masarati
Keyword(s):  
Fluid Dynamics ◽  
Differential Equations ◽  
General Purpose ◽  
Free Software ◽  
Dynamics Simulation ◽  
Flapping Wings ◽  
Navier Stokes ◽  
Element Approximation ◽  
Time Step ◽  
Naca 0012

This paper deals with the coupled structural and fluid-dynamics analysis of flexible flapping wings using multibody dynamics. A general-purpose multidisciplinary multibody solver is coupled with a computational fluid dynamics code by means of a general-purpose, meshless boundary interfacing approach based on Moving Least Squares with Radial Basis Functions. The general-purpose, free software multibody solver MBDyn is used. A nonlinear 4-node shell element has been used for the structural model. The fluid dynamics code is based on a stabilized finite element approximation of the unsteady Navier-Stokes equations. The method (often referred to in the literature as G2 method) has been implemented within the programming environment provided by the free software project FEniCS, a collection of libraries specifically designed for the automated and efficient solution of differential equations. FEniCS provides extensive scripting capabilities, with a domain-specific language for the specification of variational formulations of Partial Differential Equations that is embedded within the programming language Python. This approach makes it possible to easily and quickly build complex simulation codes that are, at the same time, extremely efficient and easily adapted to run in parallel. The coupling of the multibody and Navier-Stokes codes is strictly enforced at each time step. The fluid dynamics discretization is automatically refined to keep the error on the overall lift and drag coefficients below a user-defined tolerance. The method is first tested by computing the drag force of a non-oscillating NACA 0012 airfoil traveling in air. Subsequently, the drag and lift forces on a rigid and flexible oscillating NACA 0012 wing are compared with experimental data. Encouraging results obtained from the modeling and analysis of the dynamics and aeroelasticity of flexible oscillating wing models confirm the ability of the structural and fluid dynamics models to capture the physics of the problem.

A Survey of General Purpose Computation of GPU for Computational Fluid Dynamics

2013 ◽  
Vol 753-755 ◽  
pp. 2731-2735
Author(s):  
Wei Cao ◽  
Zheng Hua Wang ◽  
Chuan Fu Xu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Performance ◽  
Stokes Equations ◽  
Gpu Computing ◽  
Graphics Processing Unit ◽  
General Purpose ◽  
Navier Stokes ◽  
Processing Unit ◽  
Gpgpu Computing

The graphics processing unit (GPU) has evolved from configurable graphics processor to a powerful engine for high performance computer. In this paper, we describe the graphics pipeline of GPU, and introduce the history and evolution of GPU architecture. We also provide a summary of software environments used on GPU, from graphics APIs to non-graphics APIs. At last, we present the GPU computing in computational fluid dynamics applications, including the GPGPU computing for Navier-Stokes equations methods and the GPGPU computing for Lattice Boltzmann method.

scholarly journals Lift Force of Airfoil (NACA 0012, NACA 4612, NACA 6612) With Variation of Angle of Attack and Camber: Computational Fluid Dynamics Study

2021 ◽  
Vol 4 (2) ◽  
pp. 80
Author(s):  
Mariza D. Ardany ◽  
Paken Pandiangan ◽  
Moh. Hasan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Lift Force ◽  
Angle Of Attack ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
Internal Factors ◽  
Airfoil Flow ◽  
Naca 0012

Airfoil is a cross section from air plane wings can affect aerodynamic performance to lift force (FL). The lift force generated by airfoil has different values due to several external and internal factors, including angle of attack, flow rate and camber. To find the lift force of airfoils with different cambers and variations angle of attack and then flow rate can use computational fluid dynamics simulation. Computational fluid dynamics is simulation on a computer that can complete systems for fluid, heat transfer and other physical processes. This research using computational fluid dynamics simulation performed by SolidWorks, with NACA airfoil type which has different camber NACA 0012, NACA 4612 and NACA 6612. The angle of attack used in research was 0o, 4o, 8o, 12o, 16o and 20o. Flow rate used in research was 20m/s, 40 m/s, 60 m/s, 80 m/s and 100 m/s. From this research will be the bigger camber can produce a greater force lift. In addition, the greater airfoil flow rate can produce a greater force lift. This research also that the connection between force lift with coefficient lift (CL) is nonlinear quadratic form.

GPU Accelerated CFD Simulation in Electronics Cooling

2012 ◽  
Vol 263-266 ◽  
pp. 1285-1289
Author(s):  
Howard Sun ◽  
Yong Quan Zhou ◽  
Yong Sheng Liang
Keyword(s):  
Fluid Dynamics ◽  
Cfd Simulation ◽  
Electronics Cooling ◽  
Simple Algorithm ◽  
Dynamics Simulation ◽  
Massively Parallel ◽  
Navier Stokes ◽  
It Industry ◽  
Computing Power ◽  
Computer Fluid Dynamics

CFD(Computer Fluid Dynamics) simulation is widely used in IT industry, it usually based on the latest CPU computing power and software technology, can easily take hours even days. A new 3D Navier-Stokes solver based on the SIMPLE algorithm but totally rewritten from ground up with Nvidia’s CUDA software programming API was studied by investigating the use of the latest GPU technology for an electronics cooling problem. The GPU accelerated CFD simulation by using massively parallel algorithm accelerated the calculation by 3.55 times.

scholarly journals Computational fluid dynamics simulation of wind-driven inter-unit dispersion around multi-storey buildings: Upstream building effect

2017 ◽  
Vol 28 (2) ◽  
pp. 217-234 ◽  
Author(s):  
Y. W. Dai ◽  
C. M. Mak ◽  
Z. T. Ai
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Concentration Field ◽  
Mass Conservation ◽  
Dynamics Simulation ◽  
Navier Stokes ◽  
Wind Effect ◽  
Tracer Gas ◽  
Airflow Pattern ◽  
Cfd Method

Previous studies on inter-unit dispersion around multi-storey buildings focused mostly on an isolated building. Considering that the presence of an upstream building(s) would significantly modify the airflow pattern around a downstream building, this study intends to investigate the influence of such changed airflow patterns on inter-unit dispersion characteristics around a multi-storey building due to wind effect. Computational fluid dynamics (CFD) method in the framework of Reynolds-averaged Navier-stokes modelling was employed to predict the coupled outdoor and indoor airflow field, and the tracer gas technique was used to simulate the dispersion of infectious agents between units. Based on the predicted concentration field, a mass conservation based parameter, namely re-entry ratio, was used to evaluate quantitatively the inter-unit dispersion possibilities and thus assess risks along different routes. The presence of upstream building(s) could disrupt the strong impingement of approaching flows but brings a more complex and irregular airflow pattern around the downstream multi-storey buildings, leading to a more scattered distribution of re-entry ratio values among different units and uncertain dispersion routes. Generally, the tracer gas concentration in most units was lower than those in an isolated building, although very high concentrations were found in some specific areas.

Three-dimensional computational fluid dynamics simulation of valve-induced water hammer

2016 ◽  
Vol 231 (12) ◽  
pp. 2263-2274 ◽  
Author(s):  
Shuai Yang ◽  
Dazhuan Wu ◽  
Zhounian Lai ◽  
Tao Du
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Method Of Characteristics ◽  
Three Dimensional ◽  
Water Hammer ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
Time Step ◽  
Obvious Effect ◽  
Simulation Results

In this study, three-dimensional computational fluid dynamics simulation was adopted to evaluate the valve-induced water hammer phenomena in a typical tank-pipeline-valve-tank system. Meanwhile, one-dimensional analysis based on method of characteristics was also used for comparison and reference. As for the computational fluid dynamics model, the water hammer event was successfully simulated by using the sliding mesh technology and considering water compressibility. The key factors affecting simulation results were investigated in detail. It is found that the size of time step has an obvious effect on the attenuation of the wave and there exists a best time step. The obtained simulation results have a good agreement with the experimental data, which shows an unquestionable advantage over the method of characteristics calculation in predicting valve-induced water hammer. In addition, the computational fluid dynamics simulation can also provide a visualization of the pressure and flow evolutions during the transient process.

Computational Evaluation of the Periodic Performance of a NACA 0012 Fitted With a Gurney Flap

2001 ◽  
Vol 124 (1) ◽  
pp. 227-234 ◽  
Author(s):  
James C. Date ◽  
Stephen R. Turnock
Keyword(s):  
Vortex Shedding ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Time Step ◽  
Computational Evaluation ◽  
Gurney Flap ◽  
Section Design ◽  
Computationally Intensive ◽  
Lift And Drag ◽  
Naca 0012

A detailed computational investigation into the periodic two-dimensional performance of a NACA 0012 section fitted with 2 and 4 percent h/c Gurney flaps operating at a Reynolds number of 0.85×106 is presented. The aim of the work was to determine the suitability of the incompressible Reynolds-averaged Navier-Stokes (RANS) formulation in modeling the vortex shedding experienced by lifting sections with blunt, sharp edged features. In particular, whether under-converged steady state calculations could be used for section design performance evaluation in place of the computationally intensive time accurate flow simulations. Steady, periodic, and time-averaged two-dimensional lift and drag coefficients, as well as vortex shedding frequency, were predicted and compared with the available experimental data. Reasonable agreement was found, once sufficiently fine grids had been generated, and the correct time step determined for the time accurate simulations.

scholarly journals Aerodynamic shape optimization of guided missile based on wind tunnel testing and computational fluid dynamics simulation

2017 ◽  
Vol 21 (3) ◽  
pp. 1543-1554 ◽  
Author(s):  
Goran Ocokoljic ◽  
Bosko Rasuo ◽  
Aleksandar Bengin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Dynamics Simulation ◽  
Navier Stokes ◽  
Technical Institute ◽  
Aerodynamic Loads ◽  
Thrust Vector ◽  
Dynamics Simulations ◽  
The Military

This paper presents modification of the existing guided missile which was done by replacing the existing front part with the new five, while the rear part of the missile with rocket motor and missile thrust vector control system remains the same. The shape of all improved front parts is completely different from the original one. Modification was performed based on required aerodynamic coefficients for the existing guided missile. The preliminary aerodynamic configurations of the improved missile front parts were designed based on theoretical and computational fluid dynamics simulations. All aerodynamic configurations were tested in the T-35 wind tunnel at the Military Technical Institute in order to determine the final geometry of the new front parts. The 3-D Reynolds averaged Navier-Stokes numerical simulations were carried out to predict the aerodynamic loads of the missile based on the finite volume method. Experimental results of the axial force, normal force, and pitching moment coefficients are presented. The computational results of the aerodynamic loads of a guided missile model are also given, and agreed well with.

Hydrodynamics of the Interceptor Analysis Via Both Ultrareduced Model Test and Dynamic Computational Fluid Dynamics Simulation

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
M. Mansoori ◽  
A. C. Fernandes
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Dynamics Simulation ◽  
Navier Stokes ◽  
Current Channel ◽  
Computational Fluid Dynamics Cfd ◽  
Volume Method ◽  
Hydrodynamic Effects

This work investigates the hydrodynamic effects of introducing interceptors on fast vessels. Interceptors are vertical flat blades installed at the bottom of the stern vessel. They cause changes in pressure magnitudes around the vessel bottom and especially at the end of the hull where they are located. The pressure variations have an effect on resistance, draft height, and lifting forces which may result in a better control of trim. This work uses a combination of computational fluid dynamics (CFD) and ultrareduced experimental tests. The investigation applies the Reynolds-averaged Navier–Stokes (RANS) equations to model the flow around the ultrareduced model with interceptors with different heights. Our model is analyzed based on a finite-volume method using dynamic mesh. The boat motion is only with two degrees-of-freedom. The results show that the interceptor causes an intense pressure gradient, decreasing the wet surface of the vessel and, quite surprisingly, the resistance. At last, this paper shows that, within a range, a better trim control is possible. The height of the interceptor has an important effect on interceptor efficiency, and it should be especially selected according to the length of the vessel and boundary layer thickness at the transom. The ultrareduced model tests were performed in the Current Channel of the Laboratory of Waves and Current of COPPE/UFRJ (LOC in Portuguese acronym).

Computational Fluid Dynamics Simulation of Fire-Induced Air Flow in a Large Space Building: Key Points to Note

2004 ◽  
Author(s):  
Y. F. Li ◽  
W. K. Chow
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Source ◽  
Air Flow ◽  
Region Of Interest ◽  
Dynamics Simulation ◽  
Navier Stokes ◽  
Convergence Criteria ◽  
Large Space ◽  
Key Points

Fire-induced air flow in a large span building by computational fluid dynamics (CFD) will be discussed in this paper. The CFD model is based on Reynolds Averaging Navier-Stokes (RANS) equations with k-ε based turbulence model for predicting velocity, pressure and temperature distribution. This technique is commonly used in practical design for smoke management system. The fire is taken as a volumetric heat source and buoyancy effects are included in equations for the vertical momentum and turbulent parameters. Several key points to note in the simulation will be discussed. These are: • Relaxation factor and convergence criteria. • False diffusion. • Sudden changes in flow parameters across the heat source. A large terminal hall with 1 MW fire is taken as an example to discuss the above points. The fire scenarios in a region of interest will be assessed by CFD.

RANS Based Computational Fluid Dynamics Simulation of Fully Developed Turbulent Newtonian Flow in Concentric Annuli

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Xiao Xiong ◽  
Mohammad Aziz Rahman ◽  
Yan Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Turbulent Flows ◽  
Cfd Simulation ◽  
Wall Turbulence ◽  
Dynamics Simulation ◽  
Navier Stokes ◽  
Rans Model ◽  
Turbulence Structures ◽  
Fully Developed Turbulent Flow

A computational fluid dynamics (CFD) simulation is performed via ansys–CFX for a fully developed turbulent flow in concentric annuli with two radius ratios (R1/R2 = 0.4 and 0.5) at three Reynolds numbers (Re = 8900, 26,600, and 38,700) in terms of the hydraulic diameter D and the bulk velocity Ub. Near-wall turbulence structures close to the inner and outer walls are characterized by analyzing the first-order and second-order statistics. Effects of transverse curvature and the Reynolds number on development of the turbulence structures are emphasized. This study demonstrates the ability to predict the asymmetric features of turbulent flows in annular pipes by using the Reynolds-Averaged Navier–Stokes (RANS) model. Estimation of viscous dissipation in the flow using a RANS model is compared with direct numerical simulation (DNS) results for the first time.

Sign in / Sign up

Export Citation Format

Share Document