Written in EnglishRead online
|Statement||Steven A. Orszag, Cambridge Hydrodynamics, inc. ; prepared for Langley Research Center|
|Series||NASA contractor report ; NASA CR-3071, NASA contractor report -- NASA CR-3071|
|Contributions||United States. National Aeronautics and Space Administration. Scientific and Technical Information Office, Langley Research Center, Cambridge Hydrodynamics, inc|
|The Physical Object|
|Pagination||28 p. :|
|Number of Pages||28|
Download Prediction of compliant wall drag reduction, part II
Prediction of compliant wall drag reduction, part 2 A numerical model of turbulent boundary layer flows over compliant walls was investigated. The model is based on Burton's observation that outer flow structures in turbulent boundary layers produce large scale pressure fluctuations near the wall.
Drag Reduction Using Compliant Walls. January ; accurate drag measurements, compliant wall motion, and the geometry and properties of the coatings used will be among the outstanding Author: Mohamed Gad-El-Hak. Book Search tips Selecting this option will search all publications across the Scitation platform Selecting this option will Drag reduction by compliant walls The Physics of Fluids Further evaluation then requires the use of measured data.
For a certain type of compliant wall a drag reduction of 1%–10% is estimated. by: 2. Prediction of compliant wall drag reduction, part I. [Washington]: National Aeronautics and Space Administration, Scientific and Technical Information Office ; Springfield, Va.: For sale by the National Technical Information Service, (OCoLC) Material Type: Government publication, National government publication: Document Type: Book.
On the theory of compliant wall drag reduction in turbulent boundary layers A theoretical model has been developed which can explain how the motion of a compliant wall reduces turbulent skin friction drag. Available experimental evidence at low speeds has been used to infer that a compliant surface selectively removes energy from the upper frequency range of the energy containing eddies and.
the maximum drag reduction for a given maximum wall displacement is studied for the ﬁrst time. The issue of the minimum intensity of wall forcing required to produce a non-zero drag reduction eﬀect and the dependence of the drag reduction on the Reynolds number are also addressed.
The drag reduction. thermal acti vities in wall surfaces, includes wall oscillation, wall part II book and compliant wall. The interactive and active controls achieve drag reduction in a controllable way suitable for.
Drag reduction (DR) agents are used at very low concentrations to accelerate significantly the flow in oil pipeline conduits, oil well operations, flood water disposal, fire fighting, field irrigation, transport of suspensions and slurries, sewer systems, water heating and cooling systems, airplane tank filling, marine systems, and biomedical systems including blood flow.
Drag Reduction due to Streamlining and BoundaryLayer Control Civil Engineering CE Project Topics, Base Paper, Synopsis Ideas, Abstract, Report, Source Code, Full PDF, Working details for Civil Engineering, Structural, Construction, Diploma, PhD, BTech, BE, MTech and MSc College Students.
Matched shear impedance for compliant layer drag reduction, Material Science and Engineering C2, – Google Scholar FITZGERALD, J.W., FITZGERALD, E.R.
and J.E. MARTIN (a) Blubber and compliant coatings for drag reduction in water. Drag reduction in gas transmission lines. Drag reduction in gas transmission lines can be achieved by applying a thin chemical coating on the pipe’s inner surface to reduce friction between the flowing gas and pipe wall.
An important criterion for gas drag reduction is that the additive can bond strongly onto metal surfaces and form a smooth film to mitigate the turbulence at the gas. Stanewsky, E. and Krogmann, P. “Transonic Drag Rise and Drag Reduction by Active / Passive Boundary Layer Control”, AGARD Report No.Lecture Series Aircraft Drag Prediction and Reduction, July Google Scholar.
AbstractThe paper summarizes the state of the art in aeronautical drag reduction across the speed range for the “conventional” drag components of viscous drag, drag due to lift and wave drag. Aircraft drag prediction and reduction.
AGARD R, Google Scholar. On the mechanism of drag reduction of near-wall turbulence by. The state-of-the-art in aircraft drag prediction was defined as of by the AGARD conference entitled "Aerodynamic Drag."'20 This chapter draws heavily on that work and attempts to update, to the extent possible, those portions relevant to aircraft drag prediction at.
Review Paper 1 Aircraft drag reductionÐa review D M Bushnell NASA Langley Research Center, Mail StopHampton, Virginia ±, USA Abstract: The paper summarizes the state of the art in aeronautical drag reduction across the speed range for the `conventional’ drag components of viscous drag, drag due to lift and wave drag.
The issue of the minimum intensity of wall forcing required to produce a non-zero drag reduction effect and the dependence of the drag reduction on the Reynolds number are also addressed. The drag reduction data available in the literature are compared with the prediction given by the scaling parameter, thus attaining a comprehensive view of.
The CFD Drag Prediction Workshop Series: Summary and Retrospective Levy, et al DPW Workshop Series Year Location Configuration Case Descriptions Anaheim, CA DLR-F4 Wing-Body Single Point Grid Refinement Study Drag Polar Drag Rise Curves at Constant C L * Orlando, FL DLR-F6 Wing-Body Wing-Body-Nacelle.
Turbulent drag reduction by constant near-wall forcing 81 y+ F F max 40 60 – – – 0 (i) (ii) (iii) Figure 2. Proﬁles of the average streamwise force density for bubbles and particles in a. Excellent agreement is obtained between TLES and direct numerical simulations (DNS) in terms of percent drag reduction prediction.
TLES is also able to reproduce the high level of anisotropy of turbulence, which confirms recent findings by Frohnapfel et al. [ J. Fluid Mech. ()] who present high anisotropy as a general mechanism to. 4th AIAA CFD Drag Prediction Workshop Gridding Guidelines 3 November Note: The Configuration Geometry, Test Cases, and Gridding Guidelines are current as of 31 Octoberbut are subject to changes as developments require.
Please check the website periodically for updates, and/or register with [email protected] to be notified directly. An AIAA Progress Series book has also been devoted primarily to drag.8 Chapters discuss the history of drag prediction, typical methods currently used to predict drag, and the intricacies of drag prediction for complete configurations.
The most complete compilation of drag informa. Thus, (Drag)1+2 = (Drag)1 + (Drag)2 + (Drag)interference Generally, interference drag will add to the component drags but in a few cases, for example, adding tip tanks to a wing, total drag will be less than the sum of the two component drags because of the reduction of induced drag.
García-Mayoral and J. Jiménez 0 20 40 − 0 s+ Δ t / t 0 viscous regime optimum performance m s k-roughness Figure 1. Deﬁnition of the drag-reduction regimes observed over triangular riblets with 60 tip angle, as a function of the peak-to-peak distance s+.Adapted from Bechert et al..
had any real role. Flexible and rigid long chain polymers in very dilute solutions can significantly reduce the drag in turbulent flows. The polymers successively stretch and coil by interacting with the turbulent structures, which changes the turbulent flow and further imposes a transient behavior on the drag reduction (DR) as well as a subsequent mechanical polymer degradation.
13 - 3 Classification of drag according to physical causes The total drag can be subdivided into (compare with Equation ): 1.
zero-lift drag: drag without the presents of lift; 2. induced drag: drag due to lift. In addition wave drag comes into play, caused by a Mach numberM that is greater than the critical Mach number definition, Mcrit is the flight Mach number where a flow.
vehicle is responsible for a large part of the vehicle’s fuel consumption and contribute up to 50% of the total vehicle fuel consumption at highway speeds.
Review on the research performance of active and passive flow control on the vehicle aerodynamic drag reduction is reported in this paper. This. Drag reduction with the slip wall. Boundary layer drag reduction research hypotheses derived from bio-inspired surface and recent advanced applications.
Micron, Vol. Influence of Geometry Variations on the Boundary Layer Control with a Passively Moving Wall. 3 5 Approaches to analyse drag I Examine the physical mechanisms •Identify separation regions •Measure pressure and wall-shear stress •Drag obtained from surface integral •Lot of experimental data needed (unrealistic) •It is possible to find the local origins of drag D =psinϕdS +τw cosϕdS 6 •Usually possible for simple bodies (see figure) •Problem: in real cars.
"Drag Reduction of a Marine Vehicle by Electrolysis", U. Naval Academy Engineering Report EW, January,co-authored with R. Bhattacharyya. "Analysis of Motion Prediction of a Ton SES Vessel", Sea Systems, Incorporated, Report, June,co.
COVID Resources. Reliable information about the coronavirus (COVID) is available from the World Health Organization (current situation, international travel).Numerous and frequently-updated resource results are available from this ’s WebJunction has pulled together information and resources to assist library staff as they consider how to handle coronavirus.
Drag Reduction 6 FLOPAM DR Drag Reduction The shear degradation of the polymer is limited even at very high speed (25 m.s-1 or 75 ft.s) on 3 to 6 inches pipes. The shear is lower very often than s-1 in the pipe. But a part of the process is dependant on surface equipment sometimes not very adapted to the case of the polymer: high speed.
DRAG REDUCTION USING POLYMER SOLUTIONS IN GRAVITY DRIVEN FLOW SYSTEMS: Modeling [chirravuri, subbarao] on *FREE* shipping on qualifying offers. DRAG REDUCTION USING POLYMER SOLUTIONS IN GRAVITY DRIVEN FLOW SYSTEMS: Modeling.
An Eulerian two-fluid computational fluid dynamics model has been developed for flows with microbubble drag reduction (MBDR). This paper focuses on recent validation studies for MBDR flows across a spectrum of Reynolds numbers.
Direct numerical simulations and two sets of experimental flat plate boundary layer measurements are studied. Drag reduction by dilute solutions of linear, random‐coiling macromolecules in turbulent pipe flow is reviewed.
The experimental evidence is emphasized in three sections concerned with the graphical display of established features of the phenomenon, data correlation and analysis, and the physical mechanism of drag reduction. APPENDIX F: Downdrag Load (Dragload, Drag Force) and Downdrag.
F Background. Appendix F subsections: F-1 General Design Process Steps. F-2 Simplified Diagrams for Dragload Estimation. F-3 Definition of “Incompressible Material” at the Pile Toe.
F-4 Locally Adopted (MnDOT Practice) Dragload (DD) Load Factor for Neutral Plane. The total drag reduction schemes use a curve-fit routine that generates airfoil drag polars given flap angle and Reynolds number. The approximated drag polars allow the prediction of profile drag values to be combined with induced drag values to form a total drag function, which is utilized with a constrained nonlinear optimizer that determines.
Various methods of flow control for enhanced aerodynamic performance have been developed and applied to enhance and control the behavior of aerodynamic components. The use of Coandă effect for the enhancement of circulation and lift has gained renewed interest, in particular with the progress of CFD.
The present work addresses the influence, effectiveness, and configuration of Coandă-jet. The 51st volume of "International Journal of Engineering Research in Africa" includes peer-reviewed manuscripts reflecting the research results in the fields of materials science, applied mechanics, mechanical and power engineering, biomass processing, communication, construction, engineering management, and applied use of computational procedures and optimization methods in the research.
Drag Reduction Fundamentals Drag reduction by dilute solutions of linear, random-coiling macro- molecules in turbulent pipe flow is reviewed. The experimental evidence is emphasized in three sections concerned with the graphical display of estab- lished features of the phenomenon, data correlation and analysis, and the.
for low-drag models (shown by varying Cd in an altitude prediction program). Therefore, it would be a great improvement to have a list of measured Cd's which represent many of the designs, materials, and finishes used in model rocketry.
To measure the coefficient of drag, a model rocket (or plane or car) is placed in a wind tunnel with. feathers, sails, etc.) could improve drag due to lift efficiency by 10 to 15% if they are designed as an integral part of the wing.
The advantages of single winglets for small transports were investigated by Robert Jones, on which they can provide 10% reduction in induced drag compared with elliptical wings.
Winglets are being.Javadi, Kh, Farsiani, Y., Taeibi-Rahni M. Investigation of CTJ Arrangement in Boundary Layer Control from Skin Friction Drag Reduction perspective in IAS 6.
Javadi, Kh, Kazemi, K., Taeibi-Rahni M.Numerical Investigation of Natural Convection under Variable Microgarvity Gravity using LBM in IASFigs. show the pipeline flow-pressure profile atb/d and DRA concentration-drag reduction as a result of injecting gal/d of DRA at the source and gal/d at KM, downstream of.