Modeling total drag force exerted on particles in dense swarm from experimental measurements using an inline image-based method

2021 ◽  
pp. 133485
Author(s):  
Haoliang Wang ◽  
Biyu Zhang ◽  
Xiangyang Li ◽  
Yiting Xiao ◽  
Chao Yang
Keyword(s):  
Drag Force ◽  
Experimental Measurements ◽  
Total Drag

Experimental Study of Flow Control Over a Standard Road Vehicle Using Plasma Actuator

2020 ◽  
Vol 22 (4) ◽  
pp. 1047-1060
Author(s):  
S. Shadmani ◽  
S. M. Mousavi Nainiyan ◽  
R. Ghasemiasl ◽  
M. Mirzaei ◽  
S. G. Pouryoussefi
Keyword(s):  
Flow Control ◽  
Pressure Distribution ◽  
Drag Force ◽  
Separated Flow ◽  
Plasma Actuator ◽  
Road Vehicle ◽  
Slant Angle ◽  
Total Drag ◽  
Slant Surface ◽  
Ahmed Body

AbstractAhmed Body is a standard and simplified shape of a road vehicle that's rear part has an important role in flow structure and it's drag force. In this paper flow control around the Ahmed body with the rear slant angle of 25° studied by using the plasma actuator system situated in middle of the rear slant surface. Experiments conducted in a wind tunnel in two free stream velocities of U = 10m/s and U = 20m/s using steady and unsteady excitations. Pressure distribution and total drag force were measured and smoke flow visualization carried out in this study. The results showed that at U = 10m/s using plasma actuator suppress the separated flow over the rear slant slightly and be effective on pressure distribution. Also, total drag force reduces in steady and unsteady excitations for 3.65% and 2.44%, respectively. At U = 20m/s, using plasma actuator had no serious effect on the pressure distribution and total drag force.

Slip Length Measurement of Water Flow on Graphite Surface Using Atomic Force Microscope

2014 ◽  
Vol 941-944 ◽  
pp. 1581-1584 ◽  
Author(s):  
Da Yong Li ◽  
Da Lei Jing ◽  
Yun Lu Pan ◽  
Khurshid Ahmad ◽  
Xue Zeng Zhao
Keyword(s):  
Atomic Force Microscope ◽  
Water Flow ◽  
Drag Force ◽  
Silicon Surface ◽  
Slip Length ◽  
Graphite Surface ◽  
Length Measurement ◽  
Hydrodynamic Drag ◽  
Experimental Measurements ◽  
Atomic Force

In this paper, we present experimental measurements of slip length of deionized (DI) water flow on a silicon surface and a graphite surface by using atomic force microscope. The results show that the measured hydrodynamic drag force is higher on silicon surface than that on graphite surface, and a measured slip length about 10 nm is obtained on the later surface.

scholarly journals Experimental Study of Flow Control Over an Ahmed Body Using Plasma Actuator

2020 ◽  
Vol 22 (1) ◽  
pp. 239-252
Author(s):  
S. Shadmani ◽  
S. M. Mousavi Nainiyan ◽  
R. Ghasemiasl ◽  
M. Mirzaei ◽  
S. G. Pouryoussefi
Keyword(s):  
Flow Control ◽  
Pressure Distribution ◽  
Drag Force ◽  
Separated Flow ◽  
Plasma Actuator ◽  
Slant Angle ◽  
Total Drag ◽  
Slant Surface ◽  
Actuator System ◽  
Ahmed Body

AbstractAhmed Body is a standard and simplified shape of a road vehicle that's rear part has an important role in flow structure and it's drag force. In this paper flow control around the Ahmed body with the rear slant angle of 25° studied by using the plasma actuator system situated in middle of the rear slant surface. Experiments conducted in a wind tunnel in two free stream velocities of U = 10 m/s and U = 20 m/s using steady and unsteady excitations. Pressure distribution and total drag force was measured and smoke flow visualization carried out in this study. The results showed that at U = 10 m/s using plasma actuator suppress the separated flow over the rear slant slightly and be effective on pressure distribution. Also total drag force reduces in steady and unsteady excitations for 3.65% and 2.44%, respectively. At U = 20 m/s, using plasma actuator had no serious effect on the pressure distribution and total drag force.

scholarly journals WIND TUNNEL EXPERIMENT ON EFFECT OF SHAPE OF AN OBSTACLE ON TOTAL DRAG FORCE OF REGULAR ARRAY

2011 ◽  
Vol 76 (663) ◽  
pp. 485-492
Author(s):  
Aya HAGISHIMA ◽  
Jun TANIMOTO ◽  
Manato YAMAGUCHI ◽  
Yoshiki KIKUCHI
Keyword(s):  
Wind Tunnel ◽  
Drag Force ◽  
Wind Tunnel Experiment ◽  
Regular Array ◽  
Total Drag

Numerical Analysis of Lateral Skirts Performance on Drag Force of a Semi-Trailer Truck

2018 ◽  
Author(s):  
M. Lateb ◽  
H. Fellouah
Keyword(s):  
Drag Force ◽  
Aerodynamic Drag ◽  
Experimental Results ◽  
Navier Stokes ◽  
Force Parameter ◽  
Cfd Simulations ◽  
Total Drag ◽  
Computational Fluid Dynamics Cfd ◽  
Induced Flow ◽  
Relative Errors

This work performs computational fluid dynamics (CFD) simulations using a transient URANS (unsteady Reynolds averaged Navier–Stokes) turbulence model to investigate the influence of lateral skirts — located in the lower part of a semitrailer truck — in terms of reducing the total drag force and fuel consumption savings. The total drag force values are calculated for three semi-trailer trucks speeds (i.e. 60, 70 and 100 km/h), compared, and then validated against experimental results carried out in a wind tunnel reduced model scale (1:28). The relative errors of the aerodynamic drag force parameter are assessed in order to quantify the accuracy and the reliability of the numerical modeling results with regard to the experimental results. In addition, the flow pattern around the semi-trailer truck is then investigated to determine how the induced flow field is channeled, and where the recirculating zones are modified and developed when using the additional skirt device.

Numerical Analysis on the Effect of Transverse Surface Roughness in Non-Newtonian Fluid Lubrication

2005 ◽  
Author(s):  
Haosheng Chen ◽  
Yongjian Li ◽  
Darong Chen ◽  
Jiadao Wang
Keyword(s):  
Surface Roughness ◽  
Drag Force ◽  
Newtonian Fluid ◽  
Roughness Height ◽  
Navier Stokes ◽  
Lubricant Thickness ◽  
Navier Stokes Equation ◽  
Obvious Effect ◽  
Total Drag ◽  
Pressure Drag

To analyze non-Newtonian fluid lubrication with the effect of large surface roughness amplitude, Navier-Stokes equation is used and a finite volume method is adopted to acquire the lubrication results of an inclined slider model. The numerical results show that the pressure mutation occurs at the edges of surface roughness. When the roughness height is more than 1% lubricant thickness, the surface roughness takes an obvious effect on the lubrication results. The pressure drag increase as the roughness height increases, the friction drag decreases and the total drag force keeps constant. When the roughness height is more than 10% lubricant thickness, the friction force begins to increase and the total drag force increases rapidly. Non-Newtonian fluid affects the lubrication results more greatly than the surface roughness height does, but it does not affect the variation process caused by different surface roughness.

Taper stacking for the aerodynamic performance of wings

2020 ◽  
Vol 92 (7) ◽  
pp. 1101-1110
Author(s):  
Mustafa Kaya ◽  
Munir Ali Elfarra
Keyword(s):  
Mach Number ◽  
Drag Force ◽  
Angle Of Attack ◽  
Total Drag ◽  
Content Type ◽  
Critical Mach Number ◽  
Wing Sweep ◽  
Drag Ratio ◽  
First Time ◽  
Lift To Drag Ratio

Purpose The critical Mach number, lift-to-drag ratio and drag force play important role in the performance of the wings. This paper aims to investigate the effect of taper stacking, which has been used to generalize wing sweeping, on those parameters. Design/methodology/approach The results obtained are based on steady-state turbulent flowfields computations. The baseline wing is ONERA M6. Various wing planforms are generated by linearly or parabolically varying the spanwise stacking location. The critical Mach number is determined by changing the freestream Mach number for a fixed angle of attack. On the other hand, the analysis of the drag force is carried out by changing the angle of attack to keep the lift force constant. Findings By changing the stacking location, the critical Mach number and the corresponding lift-to-drag ratio have increased by around 7 and 3%, respectively. A reduction of 12.8% in total drag force has been observed in one of the analyzed cases. Moreover, there exist some cases in which the values of drag reduce significantly while the lift is the same. Practical implications The results of this new stacking approach have implied that the drag force can be decreased without decreasing the lift. This outcome is valuable for increasing the range and endurance of an aircraft. Originality/value This work generalizes wing sweeping by modifying the taper stacking along the span. In literature, wing sweep is enhanced using segmented stacking of taper distribution. The present study is further enhancing this concept by introducing continuous stacking (infinite number of stacking segments) for the first time.

scholarly journals Investigation of Drag and Lift Forces over the Profile of Car with Rearspoiler using CFD

2015 ◽  
Vol 1 (8) ◽  
pp. 331
Author(s):  
Naveen Kumar Velagapudi ◽  
Lalit Narayan K. ◽  
L. N. V. Narasimha Rao ◽  
Sri Ram Y.
Keyword(s):  
Drag Force ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Fuel Utilization ◽  
Ansys Fluent ◽  
Total Drag ◽  
Rear Spoiler ◽  
Computational Fluid Dynamics Cfd ◽  
Lift Forces ◽  
Drag And Lift

Now a days demand of a high speed car is increasing in which vehicle stability is of major concern. Forces like drag& lift,weight,side forces and thrust acts on a vehicle when moving on road which significantly effect the fuel consumption The drag force is produced by relative motion between air and vehicle and about 60% of total drag is produced at the rear end. Reduction of drag force at the rear end improves the fuel utilization. This work aims to reduce the drag force which improves fuel utilization and protects environment as well. In the stage of work a sedan car with different types of spoilers are used to reduce the aerodynamic drag force. The design of sedan car has been done on CATIA-2010 and the same is used for analysis in ANSYS-(fluent). The analysis is done for finding out drag and lift forces at different velocities, and spoilers. This study proposes an effective numerical model based on the computational fluid dynamics (CFD) approach to obtain the flow structure around a passenger car with a rear spoiler

scholarly journals Flow past a liquid drop with a large non-uniform radial velocity

1983 ◽  
Vol 133 ◽  
pp. 65-81 ◽  
Author(s):  
S. S. Sadhal ◽  
P. S. Ayyaswamy
Keyword(s):  
Radial Velocity ◽  
Drag Force ◽  
Liquid Drop ◽  
Tangential Velocity ◽  
Rigid Sphere ◽  
Normal Velocity ◽  
Total Drag ◽  
Viscous Forces ◽  
Tangential Momentum ◽  
Internal Viscosity

In this analysis, the translation of a liquid drop experiencing a strong non-uniform radial velocity has been investigated. The situation arises when a moving liquid drop experiences condensation, evaporation or material decomposition at the surface. By simultaneously treating the flow fields inside and outside the drop, we have obtained physical results relevant to the problem. The magnitude of the radial velocity is allowed to be very large, but the drop motion is restricted to slow translation. The solution to the problem has been developed by considering a uniform radial flow with the translatory motion introduced as a perturbation. The role played by the inertial terms due to the strong radial field has been clearly delineated. The study has revealed several interesting features. An inward normal velocity on a slowly moving drop increases the drag. An increasing outward normal velocity decreases the drag up to a minimum beyond which it increases. The total drag force not only consists of contributions from the viscous and the form drags but also from the momentum transport at the interface. Since the liquid drop admits a non-zero tangential velocity, the tangential momentum convected by the radial velocity forms a part of this drag force. The circulation inside the drop decreases (increases) with an outward (inward) normal velocity. A sufficiently large non-uniform outward velocity causes the circulation to reverse.In the limit of the internal viscosity becoming infinite, our analysis collapses to the simple case of a translating rigid sphere experiencing a large non-uniform radial velocity. By letting the radial velocity become vanishingly small the Stokes-flow solution is recovered.An important contribution of the present study is the identification of a new singularity in the flow description. It accounts for both the inertial and the viscous forces and displays Stokeslet-like characteristics at infinity.

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