scholarly journals Steady flow analysis of a slender wing by lifting surface method

2020 ◽  
Vol 32 ◽  
pp. 88-98
Author(s):  
Konstantin Metodiev
Keyword(s):  
Steady Flow ◽  
Algebraic System ◽  
Flow Analysis ◽  
Numerical Realization ◽  
Surface Method ◽  
Lifting Surface ◽  
Circulation Distribution ◽  
Velocity Circulation ◽  
Working Out ◽  
Slender Wing

In the paper hereby, steady flow around a thin-walled wing is analysed by means of the Lifting Surface Method. In order to carry out tests, the wing has been divided into a finite number of quadrilateral panels. All panel edges in turn are replaced by discrete straight vortex segments which induce velocities within the flow field. The problem boils down to working out velocity circulation distribution on the wing surface. For this purpose, numerical realization has been developed in C by Minimalist GNU for Windows compiler and Code::Blocks IDE. To work out a solution to the linear non-homogeneous algebraic system, the Gauss – Seidel stationary iterative method has been applied. The obtained results for various angle of attack values are depicted by means of ParaView.

A practical technique for improvement of open water propeller performance

2011 ◽  
Vol 225 (4) ◽  
pp. 375-386 ◽  
Author(s):  
S Bal
Keyword(s):  
Vortex Lattice ◽  
Open Water ◽  
Equation System ◽  
Horseshoe Vortex ◽  
Vortex Lines ◽  
Surface Method ◽  
Lifting Surface ◽  
Circulation Distribution ◽  
Propeller Performance ◽  
Lifting Line

A practical technique for the improvement of open water propeller performance has been described by using a vortex lattice lifting line method together with a lifting surface method. First, the optimum circulation distribution, giving the maximum thrust–torque ratio, has been computed along the radius of the propeller for given thrust and chord lengths, by adopting a vortex lattice solution to the lifting line problem. Then, by using the lifting surface method, the blade sectional properties such as pitch-to-diameter ratio and camber ratio, have been calculated for obtaining the desired circulation distribution. The effects of skew and rake on propeller performance have been ignored. The blades have been discretized by a number of panels extending from hub to tip. The radial distribution of bound circulation can be computed by a set of vortex elements having constant strengths. Discrete trailing free vortex lines are shed at each panel boundary, and their strengths are equal to the differences in strength of the adjacent bound vortices. The vortex system has been built from a set of horseshoe vortex elements, and they consist of a bound vortex segment and two free vortex lines of constant strengths. Each set of horseshoe vortex elements induces an axial and tangential velocity at a specified control point on the blades. An algebraic equation system can be formed by using the influencial coefficients. Once this equation system has been solved for unknown vortex strengths and specified thrust, the optimum circulation distribution and the forces can be computed by using Betz–Lerbs method. When the radial distributions of optimum circulation (loading) and chord lengths have been reached, the lifting surface method can be applied to determine the blade pitch and camber distribution. DTMB 4119 and DTMB 4381 propellers have been adopted for calculations and their hydrodynamic characteristics have been found in their open literature. A very good comparison has been obtained between the results of this practical technique and the experimental measurements.

scholarly journals Application of Two Shallow Water Models to Steady Flow Analysis in a Vegetated Agricultural Drainage Canal

2013 ◽  
Vol 19 (2) ◽  
pp. 35-41 ◽  
Author(s):  
Hidekazu Yoshioka ◽  
Nobuhiko Kinjo ◽  
Ayaka Wakazono ◽  
Koichi Unami ◽  
Masayuki Fujihara
Keyword(s):  
Shallow Water ◽  
Steady Flow ◽  
Flow Analysis ◽  
Agricultural Drainage ◽  
Drainage Canal ◽  
Shallow Water Models ◽  
Water Models

Interaction of rarefaction waves with area reductions in ducts

1983 ◽  
Vol 137 ◽  
pp. 285-305 ◽  
Author(s):  
J. J. Gottlieb ◽  
O. Igra
Keyword(s):  
Steady Flow ◽  
Rarefaction Wave ◽  
Gas Flow ◽  
Flow Analysis ◽  
Inviscid Flow ◽  
Rarefaction Waves ◽  
Area Reduction ◽  
Random Choice Method ◽  
Wave Patterns ◽  
The One

The interaction of a rarefaction wave with a gradual monotonic area reduction of finite length in a duct, which produces transmitted and reflected rarefaction waves and other possible rarefaction and shock waves, was studied both analytically and numerically. A quasi-steady flow analysis which is analytical for an inviscid flow of a perfect gas was used first to determine the domains of and boundaries between four different wave patterns that occur at late times, after all local transient disturbances from the interaction process have subsided. These boundaries and the final constant strengths of the transmitted, reflected and other waves are shown as a function of both the incident rarefaction-wave strength and area-reduction ratio, for the case of diatomic gases and air with a specific-heat ratio of 7/5. The random-choice method was then used to solve numerically the conservation equations governing the one-dimensional non-stationary gas flow for many different combinations of rarefaction-wave strengths and area-reduction ratios. These numerical results show clearly how the transmitted, reflected and other waves develop and evolve with time, until they eventually attain constant strengths, in agreement with quasi-steady flow predictions for the asymptotic wave patterns. Note that in all of this work the gas in the area reduction is initially at rest.

Optimization of Wind Turbine Blades Using Lifting Surface Method and Genetic Algorithm

2011 ◽  
Author(s):  
Xin Shen ◽  
Xiao-cheng Zhu ◽  
Zhao-hui Du
Keyword(s):  
Genetic Algorithm ◽  
Design Method ◽  
Turbine Blades ◽  
Optimization Method ◽  
Efficient Design ◽  
Wind Turbine Blades ◽  
Surface Method ◽  
Lifting Surface ◽  
Horizontal Axis Wind Turbines ◽  
Wake Model

This paper describes an optimization method for the design of horizontal axis wind turbines using the lifting surface method as the performance prediction model and a genetic algorithm for optimization. The aerodynamic code for the design method is based on the lifting surface method with a prescribed wake model for the description of the wake. A micro genetic algorithm handles the decision variables of the optimization problem such as the chord and twist distribution of the blade. The scope of the optimization method is to achieve the best trade off of the following objectives: maximum of annual energy production and minimum of blade loads including thrust and blade rood flap-wise moment. To illustrate how the optimization of the blade is carried out the procedure is applied to NREL Phase VI rotor. The result shows the optimization model can provide a more efficient design.

Iterative Lifting Surface Method for Thick Bladed Hovering Helicopter Rotors

1981 ◽  
Vol 18 (6) ◽  
pp. 417-424 ◽  
Author(s):  
K. Rajarama Shenoy ◽  
Robin B. Gray
Keyword(s):  
Helicopter Rotors ◽  
Surface Method ◽  
Lifting Surface

Paper 23: An Experimental Investigation of Non-Steady Flow in a Radial Gas Turbine

1965 ◽  
Vol 180 (10) ◽  
pp. 74-85 ◽  
Author(s):  
R. S. Benson ◽  
K. H. Scrimshaw
Keyword(s):  
Steady Flow ◽  
Mass Flow ◽  
Pulse Generator ◽  
Flow Analysis ◽  
Pulse Frequency ◽  
Exhaust Pipe ◽  
Transient Pressure ◽  
Radial Turbine ◽  
Admission Data ◽  
Partial Admission

Comprehensive steady and non-steady flow tests on a small radial turbine turbo-charger are given. Steady flow tests included both full admission and partial admission over the whole speed and pressure range from zero flow to maximum flow. Non-steady flow tests were carried out over a pulse frequency range from 30 to 70 pulses/s and turbine speeds from 30 000 to 60 000 rev/min with the turbine coupled to the exhaust system of a six-cylinder pulse generator under partial admission conditions. Extensive transient pressure and temperature measurements were taken upstream and downstream (pressure only) of the turbine. The total mass flow and power were also measured. A quasi-steady flow analysis was carried out using the steady flow test data. The tests results showed that for a six-cylinder exhaust pipe configuration, with two exhaust pipes entering separate nozzle segments in the radial turbine, the quasi-steady flow analysis using partial admission data grossly underestimated the mass flow and power output of the turbine. Using full admission data the ratio of measurement mass flow and horsepower to the calculated mass flow and horsepower was nearly always greater than unity. Furthermore, the average turbine efficiency was greater under non-steady flow than under steady flow. The magnitude of the recorded effects was dependent on the pulse frequency and turbine speed.

scholarly journals Steady flow Analysis of Gurupura River Using Hec-Ras Software

2019 ◽  
Vol 3 (1) ◽  
pp. 432
Author(s):  
Edwin Issac ◽  
Pavan Raj ◽  
Prashanth ◽  
Rudresh M Arer ◽  
Apoorva K V
Keyword(s):  
Steady Flow ◽  
Flow Analysis

Study on Mold Flow Analysis and Injection Product Verification by Analysis of Variance and Response Surface Method - Taking Toothbrush as an Example

2020 ◽  
Vol 311 ◽  
pp. 64-73
Author(s):  
Dyi Cheng Chen ◽  
Kuo Cheng Wen ◽  
Rih Sheng Yang ◽  
Yu Yu Lai
Keyword(s):  
Injection Molding ◽  
Flow Analysis ◽  
Injection Pressure ◽  
Research Process ◽  
Parameter Analysis ◽  
Surface Method ◽  
Mold Flow Analysis ◽  
Mold Flow ◽  
The Impact ◽  
Plastics Industry

With the advancement of technology, plastic products are inseparable in our environment, and the impact of the plastics industry on us is gradually increasing. Although Taiwan's plastics industry has been progressively added to mold flow analysis and automation, there are still some areas in the manufacturing process that can be optimized. In the process of slit-shaped materials, bending and deformation have a very large impact on the finished product, which is a major issue at the technical level. In this study, a toothbrush was taken as an example to find the best combination of injection molding parameters. The research process was studied from CAD mold design, CAE mold flow analysis, injection molding parameter analysis, mold opening, product injection and measurement, and the results were verified. Among them, the injection pressure, dwell time and holding pressure are used as the Taguchi factor, and the CAE mold flow analysis is performed by the direct cross table L16 (45) combination to find a small amount of warpage, and the Taguchi method and the reaction surface method are used to find out the best combination of parameters. After the final product was shot and the dimensions and simulation were compared with each other, the data showed that the amount of warpage of the finished product was 0.0892 mm, and the error with the analog value was 0.0212 mm, which confirmed that the injection molding parameters were reliable.

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