scholarly journals Effects of Bending of Fluidic Oscillators on Aerodynamic Performance of an Airfoil with a Flap

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1429
Author(s):  
Nam-Hun Kim ◽  
Kwang-Yong Kim
Keyword(s):  
Pitch Angle ◽  
Stokes Equations ◽  
Peak Velocity ◽  
Velocity Ratio ◽  
Lift Coefficient ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The present work investigated the effects of bending the outlet nozzles of fluidic oscillators installed on the NACA0015 airfoil with a flap on the flow control performance and, thus, the aerodynamic performance of the airfoil. The effects of bending on fluidic oscillators have not been reported so far in previous works. The aerodynamic analysis was performed numerically using unsteady Reynolds-averaged Navier-Stokes equations. Three different cases were considered: Case 1 changes only the bending angle with a fixed pitch angle, Case 2 changes only the pitch angle without bending, and Case 3 changes both the bending and pitch angles. Although the bending of the oscillators was introduced inevitably due to a geometrical limitation in the installation, the results indicated that the bending rather improved the lift coefficient and lift-to-drag ratio of the airfoil by improving the characteristics of the fluidic oscillators, such as the jetting angle and peak velocity ratio.

scholarly journals An Investigation of the Aerodynamic Performance for a Fuel Saving Double Channel Wing Configuration

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3911
Author(s):  
Hongbo Wang ◽  
Wenbiao Gan ◽  
Daochun Li
Keyword(s):  
Fuel Consumption ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Fuel Saving ◽  
Navier Stokes Equations ◽  
Contrastive Study ◽  
Frame Method ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Double Channel

This paper presents a fuel saving double channel wing (FADCW) configuration for a propeller driven aircraft to reduce fuel consumption. In pursuit of this objective, FADCW configuration combines the tractor propeller layout and over-the-wing propeller layout. The basic idea is to improve the wing lift-to-drag ratio by taking advantage of the beneficial propeller influence on the wing. Based on a multi reference frame method solving Reynolds averaged Navier-Stokes equations, the contrastive study of this configuration and a traditional tractor propeller-wing layout is conducted. It is shown that the propeller slipstream in the tractor propeller configuration leads to a 10.28% reduction in the wing lift-to-drag ratio. With the same reference wing area and the propeller rotation speed; however, the FADCW configuration can reduce the wing drag by 10.41% and increase its lift-to-drag ratio by 13.29%, which results in a 20.15% reduction in the fuel consumption compared with the traditional tractor propeller configuration.

scholarly journals New Aerodynamic Studies of an Adaptive Winglet Application on the Regional Jet CRJ700

Biomimetics ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 54
Author(s):  
Marine Segui ◽  
Federico R. Abel ◽  
Ruxandra M. Botez ◽  
Alessandro Ceruti
Keyword(s):  
Adaptive Design ◽  
Stokes Equations ◽  
Rotation Axis ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
High Fidelity ◽  
Navier Stokes Equations ◽  
Aerodynamic Model ◽  
Drag Ratio ◽  
Lift To Drag Ratio

This study aims to evaluates how an adaptive winglet during flight can improve aircraft aerodynamic characteristics of the CRJ700. The aircraft geometry was slightly modified to integrate a one-rotation axis adaptive winglet. Aerodynamic characteristics of the new adaptive design were computed using a validated high-fidelity aerodynamic model developed with the open-source code OpenFoam. The aerodynamic model successively uses the two solvers simpleFoam and rhoSimpleFoam based on Reynold Averaged Navier Stokes equations. Characteristics of the adaptive winglet design were studied for 16 flight conditions, representative of climb and cruise usually considered by the CRJ700. The adaptive winglet can increase the lift-to-drag ratio by up to 6.10% and reduce the drag coefficient by up to 2.65%. This study also compared the aerodynamic polar and pitching moment coefficients variations of the Bombardier CRJ700 equipped with an adaptive versus a fixed winglet.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

Simulation of Unsteady Flow Around a Cylinder

2015 ◽  
Vol 3 (2) ◽  
pp. 28-49
Author(s):  
Ridha Alwan Ahmed
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Mean Value ◽  
Navier Stokes ◽  
Cylinder Surface ◽  
Navier Stokes Equations ◽  
Flow Around A Cylinder ◽  
Numerical Grid ◽  
Good Agreement

       In this paper, the phenomena of vortex shedding from the circular cylinder surface has been studied at several Reynolds Numbers (40≤Re≤ 300).The 2D, unsteady, incompressible, Laminar flow, continuity and Navier Stokes equations have been solved numerically by using CFD Package FLUENT. In this package PISO algorithm is used in the pressure-velocity coupling.        The numerical grid is generated by using Gambit program. The velocity and pressure fields are obtained upstream and downstream of the cylinder at each time and it is also calculated the mean value of drag coefficient and value of lift coefficient .The results showed that the flow is strongly unsteady and unsymmetrical at Re>60. The results have been compared with the available experiments and a good agreement has been found between them

scholarly journals Mixing of Particles in Micromixers under Different Angles and Velocities of the Incoming Water

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 577 ◽  
Author(s):  
Evangelos Karvelas ◽  
Christos Liosis ◽  
Theodoros Karakasidis ◽  
Ioannis Sarris
Keyword(s):  
Stokes Equations ◽  
Velocity Ratio ◽  
The Other ◽  
Navier Stokes ◽  
Contaminated Water ◽  
Solution Flow ◽  
Navier Stokes Equations ◽  
Inlet Velocity ◽  
Metal Capture ◽  
Discrete Motion

A possible solution for water purification from heavy metals is to capture them by using nanoparticles in microfluidic ducts. In this technique, heavy metal capture is achieved by effectively mixing two streams, a nanoparticle solution and the contaminated water. In the present work, particles and water mixing is numerically studied for various inlet velocity ratios and inflow angles of the two streams. The Navier-Stokes equations are solved for the water flow while the discrete motion of particles is evaluated by a Lagrangian method. Results showed that as the velocity ratio between the inlet streams increases, by increasing the particles solution flow, the mixing of particles with the contaminated water is increased. Thus, nanoparticles are more uniformly distributed in the duct. On the other hand, angle increase between the inflow streams ducts is found to be less significant.

scholarly journals Instability of transonic flow past flattened airfoils

2013 ◽  
Vol 3 (4) ◽  
Author(s):  
Alexander Kuzmin
Keyword(s):  
Numerical Modeling ◽  
Transonic Flow ◽  
Stokes Equations ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Simulations ◽  
Flow Past ◽  
Coefficient Versus

AbstractTransonic flow past a Whitcomb airfoil and two modifications of it at Reynolds numbers of the order of ten millions is studied. The numerical modeling is based on the system of Reynolds-averaged Navier-Stokes equations. The flow simulations show that variations of the lift coefficient versus the angle of attack become more abrupt with decreasing curvature of the airfoil in the midchord region. This is caused by an instability of closely spaced local supersonic regions on the upper surface of the airfoil.

Numerical Investigations of Arched Vortex Characteristics Generated at T-Junction Piping Systems

2004 ◽  
Author(s):  
Toshiharu Muramatsu
Keyword(s):  
Stokes Equations ◽  
Velocity Ratio ◽  
Navier Stokes ◽  
Fluid Temperature ◽  
Simulation Code ◽  
Navier Stokes Equations ◽  
Downstream Region ◽  
Piping Systems ◽  
Frequency Components ◽  
Thermal Striping

Thermohydraulic analyses for a fundamental water experiment simulating thermal striping phenomena at T-junction piping systems were carried out using a quasi-direct numerical simulation code DINUS-3, which is represented by instantaneous Navier-Stokes equations and deals with a modified third-order upwind scheme for convection terms. Calculated results were compared with experimental results on the flow patterns in the downstream region of the systems, the arched vortex structures under a deflecting jet condition, the generation frequency of the arched vortex, etc. in the various conditions; i.e., diameter ratio α, flow velocity ratio β and Reynolds number Re. From the comparisons, it was confirmed that (1) the DINUS-3 code is applicable to the flow pattern classifications in the downstream region of the T-junction piping systems, (2) the arched vortex characteristics with lower frequency components and their generation possibilities can be estimated numerically by the DINUS-3 code, and (3) special attentions should be paid to the arched vortex generations with lower frequency components of fluid temperature fluctuations in the design of T-junction systems from the viewpoints of the avoidances for the thermal striping.

scholarly journals Effect of Leading-Edge Bulges on Aerodynamic Characteristics of Bionic Wingsail

2021 ◽  
Author(s):  
Chen Li ◽  
Peiting Sun ◽  
Hongming Wang
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Suction Surface ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Extension Direction ◽  
Lift And Drag

The leading-edge bulges along the extension direction are designed on the marine wingsail. The height and the spanwise wavelength of the protuberances are 0.1c and 0.25c, respectively. At Reynolds number Re=5×105, the Reynolds Averaged Navier-Stokes equations are applied to the simulation of the wingsail with the bulges thanks to ANSYS Fluent finite-volume solver based on the SST K-ω models. The grid independence analysis is carried out with the lift and drag coefficients of the wingsail at AOA = 8° and AOA=20°. The results show that while the efficiency of the wingsail is reduced by devising the leading-edge bulges before stall, the bulges help to improve the lift coefficient of the wingsail when stalling. At AOA=22° under the action of the leading-edge tubercles, a convective vortex is formed on the suction surface of the modified wingsail, which reduces the flow loss. So the bulges of the wingsail can delay the stall.

Optimization of a Fan Blade Cascade Using the Parametric Flow Solver Turb’Opty

2006 ◽  
Author(s):  
S. Moreau ◽  
S. Aubert ◽  
G. Grondin ◽  
P. Ferrand
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Taylor Series Expansion ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Free Jet ◽  
Engine Cooling ◽  
Blade Cascade ◽  
Fan Blade

The parameterized CFD solver Turb’Opty™, based on a Taylor series expansion to high order derivatives of the solution of the discretized Navier-Stokes equations, has been successfully applied to the full geometric and flow parameterization of an engine cooling fan blade cascade. The coupling of a recently developed genetic algorithm and the post-processor Turb’Post™ has also yielded a multi-objective optimization of the original Valeo airfoil. A representative geometry of the Pareto front has then been prototyped and tested. Significant improvement of the lift coefficient has been obtained at all incidences. Comparisons with direct Turb’Flow™ cascade results have validated the accuracy of the parameterized solutions and shown the same trend as the free-jet measurements.

Velocity Characteristics of Confined Coaxial Jets With and Without Swirl

1980 ◽  
Vol 102 (1) ◽  
pp. 47-53 ◽  
Author(s):  
M. A. Habib ◽  
J. H. Whitelaw
Keyword(s):  
Stokes Equations ◽  
Swirling Flow ◽  
Laser Doppler Anemometry ◽  
Velocity Ratio ◽  
Equation Model ◽  
Navier Stokes ◽  
Recirculation Region ◽  
Jet Flows ◽  
Mean Velocity ◽  
Navier Stokes Equations

Measured values of the velocity characteristics of turbulent, confined, coaxial-jet flows have been obtained, without swirl, for ratios of maximum annulus to pipe velocities of 1.0 and 3.0 and with a swirl number of 0.23 for a velocity ratio of 3.0. They were obtained by a combination of pressure probes, hot-wire and laser-Doppler anemometry. The results are compared with calculations, based on the solution of finite-difference forms of the steady, Navier-Stokes equations, and an effective-viscosity hypothesis. The measurements allow the influence of confinement and swirl to be quantified and show, for example, the increased tendency towards centerline recirculation which results from both. The results with the three types of instrumentation allow a comparison within the corner recirculation region which reveals that serious errors of interpretation of mean-velocity measurements need not arise. The two-equation model, although able to represent the non-swirling flow is less appropriate to the swirling flow and the reasons are indicated.

Sign in / Sign up

Export Citation Format

Share Document