Lift, Drag, and Pressure Distribution Effects Accompanying Drag-Reducing Polymer Injection on Two-Dimensional Hydrofoil

1975 ◽  
Author(s):  
Daniel H. Fruman ◽  
Marshall P. Tulin ◽  
Han-Lieh Liu
Keyword(s):  
Pressure Distribution ◽  
Two Dimensional ◽  
Polymer Injection ◽  
Drag Reducing Polymer

Lift Effects Associated with Drag-Reducing Polymer Injection on Two-Dimensional Hydrofoils

1976 ◽  
Vol 20 (03) ◽  
pp. 145-151
Author(s):  
Daniel H. Fruman
Keyword(s):  
Injection Velocity ◽  
Pressure Side ◽  
Two Dimensional ◽  
Foil Surface ◽  
Freestream Velocity ◽  
Polymer Injection ◽  
Drag Reducing Additive ◽  
Lift And Drag ◽  
Drag Reducing Polymer ◽  
Drag Ratio

The effect of a boundary-layer injection of drag-reducing additive solutions on the lift and drag of a 10-cm chord, NACA 63A020 symmetrical two-dimensional hydrofoil was investigated for various freestream and injection velocities, foil incidences, and additive concentrations ranging from 50 to 400 ppm of POLYOX WSR 301. The experimental results demonstrate that the lift of the hydrofoil can either increase or decrease depending upon whether the polymer injection is made on the suction or pressure side of the foil surface, respectively. In both cases, however, the drag is reduced. The net result of the injection of the drag-reducing agent is an augmentation of the lift-drag ratio. The magnitude of this augmentation and its dependence on the freestream velocity, the injection velocity, the concentration of polymer, and the incidence of the foil are analyzed.

Effect of Compressibility on Gaseous Flows in a Micro-Tube

2003 ◽  
Author(s):  
Yutaka Asako ◽  
Kenji Nakayama
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Pressure Distribution ◽  
Flow Characteristics ◽  
Fused Silica ◽  
Two Dimensional ◽  
Arbitrary Lagrangian Eulerian ◽  
Gaseous Flow ◽  
Gaseous Flows ◽  
Energy Equations

The product of friction factor and Reynolds number (f·Re) of gaseous flow in the quasi-fully developed region of a micro-tube was obtained experimentally and numerically. The tube cutting method was adopted to obtain the pressure distribution along the tube. The fused silica tubes whose nominal diameters were 100 and 150 μm, were used. Two-dimensional compressible momentum and energy equations were solved to obtain the flow characteristics in micro-tubes. The numerical methodology is based on the Arbitrary-Lagrangian-Eulerian (ALE) method. The both results agree well and it was found that (f·Re) is a function of Mach number.

Generalisation of the Condition for Waviness in the Pressure Distribution on a Cambered Plate

1963 ◽  
Vol 67 (632) ◽  
pp. 529-530 ◽  
Author(s):  
E. Angus Boyd
Keyword(s):  
Pressure Distribution ◽  
Surface Pressure ◽  
Leading Edge ◽  
Metal Plate ◽  
Two Dimensional ◽  
Striking Result ◽  
Surface Pressure Distribution

Recently some data from tests done on a cambered plate have been published. The shape of metal plate aerofoil tested matched that taken up by a flexible two-dimensional sail. The most striking result in the rneasurements was the waviness present near the leading edge in the upper surface pressure distribution. To find the theoretical conditions under which such a waviness would occur a parabolic skeleton aerofoil was investigated, as this shape differed little from the actual aerofoil tested.

Two-dimensional pressure field and backflow in the annular skirt of vortex gripper

2020 ◽  
pp. 095440622097404
Author(s):  
Jianghong Zhao ◽  
Xin Li
Keyword(s):  
Flow Field ◽  
Pressure Distribution ◽  
Local Stress ◽  
Vortex Chamber ◽  
Physical Contact ◽  
Two Dimensional ◽  
Stress Concentrations ◽  
Suction Force ◽  
Maximum Value ◽  
Gap Height

The vortex gripper is a kind of pneumatic noncontact gripper that does not produce a magnetic field and heat. It can grip a workpiece without physical contact, which avoids any unintentional damage such as mechanical scratches, local stress concentrations, frictional static electricity, and surface stains. This study focused on the two-dimensional pressure distribution field on a workpiece surface under the vortex gripper. Theoretical, experimental, and computational fluid dynamics results were combined to study the backflow phenomenon in the annular skirt, which can decrease the gripper’s suction force after the maximum value is reached. First, the pressure distribution in the annular skirt was theoretically modeled. A comparison with the experimental results showed that increasing the gap height between the gripper and workpiece generates a circumferentially asymmetrical flow field in the skirt. Based on this, it was hypothesized that an airflow in the circumferential direction may exist. The experimental data and simulation results were analyzed under large gap height conditions to observe the backflow in detail and it was found that an uneven pressure distribution with positive and negative pressure regions generated by the uneven flow is the root cause of the backflow. Finally, the effect of the backflow on the flow field in two different flow regions (in the annular skirt and inside the vortex chamber) was analyzed and the reason why the suction force of the vortex gripper has a maximum value was determined.

Direct Design of Ducts

2003 ◽  
Vol 125 (1) ◽  
pp. 158-165 ◽  
Author(s):  
A. Ashrafizadeh ◽  
G. D. Raithby ◽  
G. D. Stubley
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pressure Distribution ◽  
Design Method ◽  
Three Dimensional ◽  
Viscous Flows ◽  
Simple Extension ◽  
Two Dimensional ◽  
Direct Design ◽  
Dependent Variables

This paper describes a method for calculating the shape of duct that leads to a prescribed pressure distribution on the duct walls. The proposed design method is computationally inexpensive, robust, and a simple extension of existing computational fluid dynamics methods; it permits the duct shape to be directly calculated by including the coordinates that define the shape of the duct wall as dependent variables in the formulation. This “direct design method” is presented by application to two-dimensional ideal flow in ducts. The same method applies to many problems in thermofluids, including the design of boundary shapes for three-dimensional internal and external viscous flows.

A Design Method and the Performance of Two-Dimensional Turbine Cascades for High Subsonic Flow

1971 ◽  
Author(s):  
A. Uenishi
Keyword(s):  
Approximate Solution ◽  
Pressure Distribution ◽  
Subsonic Flow ◽  
Design Method ◽  
Two Dimensional ◽  
Hodograph Method ◽  
Numerical Examples ◽  
Turbine Cascades ◽  
Measured Pressure ◽  
High Subsonic Flow

This paper deals with a hodograph method for design of turbine cascades in high subsonic flow and an approximate solution to a gas, specific heat ratio γ = −1 (the Karman-Tsien approximation) and γ > 1 (the gas obeying the adiabatic law). Numerical examples and a comparison of theoretical and measured pressure distribution for profiles designed by this method are given. Further, a better criterion for design to improve cascade efficiency is also presented.

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