2 edition of Turbulent flow drag reduction at elevated temperatures. found in the catalog.
Turbulent flow drag reduction at elevated temperatures.
Aroon Vasudev Shenoy
MScthesis, Chemical Engineering.
The drag reduction under turbulent flow conditions is higher when compared to the results from a quasi-steady analysis. The quasi-steady analysis under predicts the drag reduction. Under light wind conditions the unsteady time averaged drag is about lower when compared to the quasi-steady drag value. Drag reduction by polymer additives in turbulent pipe flow, Surfactant drag reduction in a turbulent recirculating pipe flow at high temperatures. Vadim Uritsky. Education: , Mechanical Engineering, University of Alberta () Email: [email protected] Office: C Mechanical Engineering Building Start Date: May Supervisor: Dr. Sina.
Title: Turbulent Pipe Flow Drag Reduction with Narrow Distribution Polystyrene Materials A Test of Drag Reduction Theories Abstract approved: W. E. (Skip) Rochefort The goal of the present studies is to test the "Time Scale" theories of the turbulent drag reduction in pipe flow with the use of dilute solutions of high molecular weight. Taking an elevated elongational viscosity into account, a qualitative explanation of drag reduction has been given by Landahl: he suggests that the elongational viscosity can suppress the occurrence of streaks—regions of flow with a highly elongational part—in the turbulent boundary layer. These boundary layer instabilities lead to 'blobs Cited by:
Therefore, it is difficult to decrease the skin-friction drag in turbulent flow. In a recent report, Hiroya Mamori and colleagues showed traveling wave control of turbulent flow. Abstract. 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.
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Drag Reduction of Turbulent Flows by Additives is the first treatment of the subject in book form. The treatment is extremely broad, ranging from physicochemical to hydromechanical aspects.
The book shows how fibres, polymer molecules or surfactants at very dilute concentrations can reduce the drag of turbulent flow, leading to energy savings. The system shows normal turbulent flow behaviour at room temperature, but depicts an ability to reduce friction when flowing at a temperature at and around its cloud point.
The consequences of this elevated temperature drag reduction have been discussed from the viewpoint of using drag reducers in central heating by: turbulent flow drag reduction. Introduction In Toms reported that very dilute solutions of polymethyl methacrylate in monochlorobenzene could cause large reductions in the turbulent pipe flow pressure drop relative to that obtained with the pure solvent at the same flow-rate (typically a 50 % reduction for a yo solution).
This. Drag reduction in turbulent flow on a passive superhydrophobic surface is small at low Re’s and increases to a maximum of 22% at Re = 80, whereas the turbulent drag reduction on our low-temperature Leidenfrost surface approaches Cited by: Stereoscopic PIV measurement was performed for a water flow (Re=×) and a CTAC solution flow (Re=× with 54% drag reduction) in both the.
A few years later Metzner and Park achieved what they termed indicative success in attempting to correlate the degree of drag reduction in the turbulent flow of viscoelastic polymer solutions with the ratio of elastic to viscous stress, i.e.
with N 1 /τ S where N 1 is the first normal-stress difference for a given wall shear rate γ ̇ and τ S the corresponding wall shear by: Turbulent flow drag reduction at elevated temperatures. book new area of practical drag reduction involves exploiting many years of research in boundary layer control, particularly techniques to maintain laminar flow over large surface areas.
Boeing is introducing hybrid laminar flow control on the horizontal and vertical stabilizers on their new stretched B in an attempt to reduce profile drag by 1%. A REVIEW OF DRAG REDUCTION BY RIBLETS AND MICRO-TEXTURES IN THE TURBULENT BOUNDARY LAYERS.
Samira Sayad Saravi, PhD. Kai Cheng, Prof. School of Engineering and Design, Brunel University, Uxbridge, London, UK. Abstract. Drag reduction in wall-bounded flows can be achieved by the passive flow control technique, riblets.
An Internet Book on Fluid Dynamics Drag on a Sphere and Cylinder It is useful to illustrate the complexity of the ﬂow around an object, the changes with Reynolds number and the consequent changes in the drag by way of an example.
The most studied example is the ﬂowFile Size: KB. Sustained drag reduction in a turbulent flow using a low-temperature Leidenfrost surface Dhananjai Saranadhi,1* Dayong Chen,2* Justin A.
Kleingartner,2 Siddarth Srinivasan,2,3 Robert E. Cohen,2† Gareth H. McKinley1† Skin friction drag contributes a major portion of the total drag for small and large water vehicles at high ReynoldsCited by: Rather, we find that for these conditions a dramatic global drag reduction of up to 45 % occurs.
We connect this global result to our local observations, showing that for major drag reduction the vapour bubble deformability is crucial, corresponding to Weber numbers larger than one. Eurom on drag reduction in turbulent flows due to additives, was held from August in Stockholm, Sweden, under the chairmanship of M.
Landahl, and was intended to bring together specialists in the various aspects of the drag-reduction phenomenon to. Experiments were carried out in a fully developed turbulent channel flow of half-height h = cm, width 75 cm and length m. (A description of the Cited by: The remarkable ability of polymeric additives to reduce the level of frictional drag significantly in turbulent flow, even under extremely low dilutions, is known as turbulent drag-reduction behavior.
Drag reduction in turbulent channel flow over spatially periodic surfaces Visualization of flow over a thick airfoil with circular cross-sectional riblets at low Reynolds numbers 20 July | Journal of Visualization, Vol.
22, No. Turbulent drag reduction by additives is a striking phe-nomenon in which the presence of small quantities of addi-tives in a carrier ﬂuid can reduce turbulent friction greatly compared with the pure ﬂuid at the same ﬂow rate. There are several kinds of drag reducers including surfactants, polymers,bubbles,andﬁbers,whicharepromisingforsaving.
Flow Improver Solutions for Pipeline Drag Reduction Pipeline Technology Conference. Hannover, Germany. during turbulent flow. Flow Improver Solutions 0 1, 1, 2, 2, Handling temperatures to 44° C: Hazard to transport, store & handle.
Non-hazardous:File Size: KB. Turbulent Drag Reduction by Biopolymers in Large Scale Pipes Marina Campolo, Measurement of Temperature Profiles in Turbulent Pipe Flow of Polymer and Surfactant Drag-Reducing Solutions,” Phys.
Fluids, 19 (8), p. Investigation On Energy Loss in Centrifugal Pump Based On Entropy Generation and High-Order Spectrum by: Abstract. Nature has created ways of reducing drag in fluid flow, evident in the efficient movement of fish, dolphins, and sharks.
The mucus secreted by fish reduces drag as they move through water, protects the fish from abrasion by making the fish slide across objects rather than scrape, and prevents disease by making the surface of the fish difficult for microscopic organisms to adhere to Cited by: 5.
Shark-skin surfaces for fluid-drag reduction in turbulent flow: a review Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol.
No. Research on Optimization Design of Bottom Angle of Drag-Reducing Structure on the Riblets Surface. Turbulent flow, type of fluid (gas or liquid) flow in which the fluid undergoes irregular fluctuations, or mixing, in contrast to laminar flow, in which the fluid moves in smooth paths or turbulent flow the speed of the fluid at a point is continuously undergoing changes in both magnitude and direction.
The flow of wind and rivers is generally turbulent in this sense, even if the.Saranadhi, D., et al., Sustained drag reduction in a turbulent flow using a low-temperature Leidenfrost surface. Science Advances, 2 (10).Turbulent flow is a difficult issue in fluid dynamics, the rules of which have not been totally revealed up to now.
Fluid in turbulent state will result in a greater frictional force, which must consume great energy. Therefore, it is not only an important influence in saving energy and improving energy utilization rate but also an extensive application prospect in many fields, such as ship Cited by: 6.