A Method for Inverse Aerofoil and Cascade Design by Surface Vorticity

1982 ◽  
Author(s):  
R. I. Lewis
Keyword(s):  
Velocity Distribution ◽  
Incompressible Flow ◽  
Design Tool ◽  
The Body ◽  
Surface Velocity ◽  
Classical Solutions ◽  
Analysis Tool ◽  
Attached Flow ◽  
Turbomachine Blade

Surface vorticity theory, normally considered as an analysis tool, has been modified to operate as a design tool whereby the shapes of components may be found to produce a prescribed surface velocity in incompressible flow. The basis of the method is presented and checked against classical solutions for cylindrical and diamond shaped struts with fully attached flow. A procedure for turbomachine blade or aerofoil design is outlined and illustrated with back checks via Martensen’s method. The method allows specification of velocity distribution on either or both surfaces of the body. If only one surface of an aerofoil or blade is prescribed, the user is allowed to specify profile thickness also.

Incipient Separation Near Corners

2018 ◽  
Author(s):  
Anatoly I. Ruban
Keyword(s):  
Corner Point ◽  
Analytic Form ◽  
The Body ◽  
Recirculation Region ◽  
Body Contour ◽  
Concave Corner ◽  
Attached Flow ◽  
Surface Deflection ◽  
Interaction Problem ◽  
Incipient Separation

Chapter 4 analyses the transition from an attached flow to a flow with local recirculation region near a corner point of a body contour. It considers both subsonic and supersonic flow regimes, and shows that the flow near a corner can be studied in the framework of the triple-deck theory. It assumes that the body surface deflection angle is small, and formulates the linearized viscous-inviscid interaction problem. Its solution is found in an analytic form. It also presents the results of the numerical solution of the full nonlinear problem. It shows how, and when, the separation region forms in the boundary layer. In conclusion, it suggests that in the subsonic flow past a concave corner, the solution is not unique.

scholarly journals Inspection planning by defect prediction models and inspection strategy maps

2021 ◽  
Author(s):  
Elisa Verna ◽  
Gianfranco Genta ◽  
Maurizio Galetto ◽  
Fiorenzo Franceschini
Keyword(s):  
Probabilistic Models ◽  
Prediction Models ◽  
Design Tool ◽  
General Interest ◽  
Manufacturing Processes ◽  
Analysis Tool ◽  
Manufacturing Companies ◽  
Inspection Planning ◽  
Inspection Strategy ◽  
Defect Prediction Models

AbstractDesigning appropriate quality-inspections in manufacturing processes has always been a challenge to maintain competitiveness in the market. Recent studies have been focused on the design of appropriate in-process inspection strategies for assembly processes based on probabilistic models. Despite this general interest, a practical tool allowing for the assessment of the adequacy of alternative inspection strategies is still lacking. This paper proposes a general framework to assess the effectiveness and cost of inspection strategies. In detail, defect probabilities obtained by prediction models and inspection variables are combined to define a pair of indicators for developing an inspection strategy map. Such a map acts as an analysis tool, enabling positioning assessment and benchmarking of the strategies adopted by manufacturing companies, but also as a design tool to achieve the desired targets. The approach can assist designers of manufacturing processes, and particularly low-volume productions, in the early stages of inspection planning.

Pure Design Method for Aerofoils in Cascade

1969 ◽  
Vol 11 (5) ◽  
pp. 454-467 ◽  
Author(s):  
K. Murugesan ◽  
J. W. Railly
Keyword(s):  
Exact Solution ◽  
Velocity Distribution ◽  
Design Problem ◽  
Design Method ◽  
Tangential Velocity ◽  
Surface Velocity ◽  
Normal Velocity ◽  
Blade Design ◽  
Blade Shape

An extension of Martensen's method is described which permits an exact solution of the inverse or blade design problem. An equation is derived for the normal velocity distributed about a given contour when a given tangential velocity is imposed about the contour and from this normal velocity an initial arbitrarily chosen blade shape may be successively modified until a blade is found having a desired surface velocity distribution. Five examples of the method are given.

An Approximate Solution for Incompressible Flow About an Ellipsoid Near a Plane Wall

1950 ◽  
Vol 17 (2) ◽  
pp. 154-158
Author(s):  
Phillip Eisenberg
Keyword(s):  
Approximate Solution ◽  
Velocity Distribution ◽  
Closed Form ◽  
Incompressible Flow ◽  
Velocity Potential ◽  
Plane Wall ◽  
Wall Effect ◽  
Pressure Distributions

Abstract Using the method of successive images, an approximate solution for the velocity potential is obtained in closed form for incompressible flow about an ovary ellipsoid near a plane wall. The velocity distribution is computed from this solution in two ways. The first computation properly predicts differences in velocities on opposite half-meridians of the ellipsoid. A second method results in a symmetric velocity distribution but is useful for rapid estimates of the average wall effect. Pressure distributions calculated by this theory are compared with values measured on 4:1 and 6:1 ellipsoid models.

Fatigue Life Analysis of Offshore Wind Turbine Support Structures in an Offshore Wind Farm

2018 ◽  
Author(s):  
Bryan Nelson ◽  
Yann Quéméner
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
The Body ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Analysis Tool ◽  
Support Structures ◽  
Offshore Wind Farm ◽  
Actuator Disk

This study evaluated, by time-domain simulations, the fatigue lives of several jacket support structures for 4 MW wind turbines distributed throughout an offshore wind farm off Taiwan’s west coast. An in-house RANS-based wind farm analysis tool, WiFa3D, has been developed to determine the effects of the wind turbine wake behaviour on the flow fields through wind farm clusters. To reduce computational cost, WiFa3D employs actuator disk models to simulate the body forces imposed on the flow field by the target wind turbines, where the actuator disk is defined by the swept region of the rotor in space, and a body force distribution representing the aerodynamic characteristics of the rotor is assigned within this virtual disk. Simulations were performed for a range of environmental conditions, which were then combined with preliminary site survey metocean data to produce a long-term statistical environment. The short-term environmental loads on the wind turbine rotors were calculated by an unsteady blade element momentum (BEM) model of the target 4 MW wind turbines. The fatigue assessment of the jacket support structure was then conducted by applying the Rainflow Counting scheme on the hot spot stresses variations, as read-out from Finite Element results, and by employing appropriate SN curves. The fatigue lives of several wind turbine support structures taken at various locations in the wind farm showed significant variations with the preliminary design condition that assumed a single wind turbine without wake disturbance from other units.

scholarly journals EFFECT OF AWARENESS, KNOWLEDGE AND ATTITUDE OF TAXPAYERS TAX COMPLIANCE FOR TAXPAYERS IN TAX SERVICE OFFICE BOYOLALI

2017 ◽  
Vol 1 (01) ◽  
Author(s):  
Monot Wicaksono ◽  
Tutik Lestari
Keyword(s):  
Regression Analysis ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Tax Compliance ◽  
The Body ◽  
Primary Data ◽  
Analysis Tool ◽  
Tax Revenues ◽  
Convenience Sampling ◽  
Knowledge And Attitude

Tax compliance is a major factor affecting tax revenues. To determine the level of compliance of taxpayers in meeting their tax obligations can be seen from the achievement of revenue targets. This research aims to analyzing the influence of taxpayers’ awareness, knowledge of taxation, and taxpayers’ attitude influential on of docility taxpayers in KPP Pratama Boyolali. Convenience sampling was conducted in this research as a method. Data obtained in the form of primary data questionnaire distributed in KPP Pratama Boyolali and data obtained secondary from KPP Pratama Boyolali. Taxpayers taken as sampled was taxpayers who came to KPP Pratama Boyolali who have NPWP good taxpayers people personally and the body was handed SPT in KPP Pratama Boyolali. This research used Multiple Regression analysis tool. The result of research shows that awareness taxpayers influential significantly against of docility taxpayers. The knowledge of the tax is not influential significantly against of docility taxpayers The attitude of the taxpayers significantly influences taxpayer compliance. Keywords: taxpayer awareness, knowledge of taxation, attitude of the taxpayer on tax compliance.

ASSESSMENT OF MULTALL AS CFD CODE FOR THE ANALYSIS OF TUBE-AXIAL FANS

2021 ◽  
pp. 1-12
Author(s):  
Piero Danieli ◽  
Massimo Masi ◽  
Giovanni Delibra ◽  
Alessandro Corsini ◽  
Andrea Lazzaretto
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Velocity Distribution ◽  
High Speed ◽  
State Of The Art ◽  
Stable Operation ◽  
Pressure Curve ◽  
Analysis Tool ◽  
Low Speed ◽  
Axial Fans

Abstract This work deals with the application of the open source CFD code MULTALL to the analysis of tube-axial-fans. The code has been widely validated in the literature for high-speed turbomachine flows but not applied yet to low speed tutbomachines. The aim of this work is to assess the degree of reliability of MULTALL as a tool for simulating the internal flow in industrial axial-flow fan rotors. To this end, the predictions of the steady-state air flow field in the annular sector of a 315 mm tube-axial fan obtained by MULTALL 18.3 are compared with those obtained by two state-of-the-art CFD codes and experimental data of the global aerodynamic performance of the fan and the pitch-wise averaged velocity distribution downstream of the rotor. All the steady-state RANS calculations were performed on either fully structured hexahedron or hexa-dominant grids using classical formulations of algebraic turbulence models. The pressure curve and the trend of the aeraulic efficiency in the stable operation range of the fan predicted by MULTALL show very good agreement with both the experimental data and the other CFD results. Although the estimation of the fan efficiency predicted by MULTALL can be noticeably improved by the more sophisticated state-of-the-art CFD codes, the analysis of the velocity distribution at the rotor exit supports the use of MULTALL as a reliable CFD analysis tool for designers of low-speed axial fans.

Integrating an Electronics Component Database Into a Thermal Design Tool

2009 ◽  
Author(s):  
Patrick Loney
Keyword(s):  
Human Error ◽  
Thermal Characteristics ◽  
Design Tool ◽  
Thermal Design ◽  
Junction Temperature ◽  
Analysis Tool ◽  
Resistance Performance ◽  
Business Sectors ◽  
Component Database ◽  
Pin Configuration

When developing a thermal model of a highly populated electronics board, a significant amount of time and effort is needed to track the thermal characteristics of all the dissipating components. In business sectors where multiple boards are thermally designed and analyzed each year, developing a components database and integrating it into the analysis tool will save time and ensure that consistent values are used in every design. With an “in tool” component database, multiple advantages are achieved. Once a component is entered into the database, the component information can be accessed in subsequent designs that employ the component. All engineers doing thermal design have access to the database. Once the thermal characteristics of a component are agreed upon, consistency across all boards is maintained. Additionally, values for each component in the database can be automatically brought into the analysis tool. By making a computer program develop the model of the component, human error is removed. The database tracks all major thermal aspects of a component. This includes the maximum junction temperature, Theta JC (case to junction resistance), leg/pin configuration (size, length, number, conductivity), and board to case gap thickness. Optional values can include top side cooling resistance, performance temperature limits, manufacturer, datasheet web address, and even an entry to identify the configuring engineer.

Impairments of Postural Balance in Surgically Treated Lumbar Disc Herniation Patients

2020 ◽  
Vol 36 (4) ◽  
pp. 228-234
Author(s):  
Ziva M. Rosker ◽  
Jernej Rosker ◽  
Nejc Sarabon
Keyword(s):  
Postural Balance ◽  
Center Of Pressure ◽  
Balance Control ◽  
The Body ◽  
Surface Velocity ◽  
Body Sway ◽  
Support Surface ◽  
Balance Task ◽  
Lateral Body ◽  
Unstable Support

Reports on body sway control following microdiscectomy lack reports on side-specific balance deficits as well as the effects of trunk balance control deficits on body sway during upright stances. About 3 weeks post microdiscectomy, the body sway of 27 patients and 25 controls was measured while standing in an upright quiet stance with feet positioned parallel on an unstable support surface, a tandem stance with the involved leg positioned in front or at the back, a single-leg stance with both legs, and sitting on an unstable surface. Velocity, average amplitude, and frequency-direction–specific parameters were analyzed from the center of pressure movement, measured by the force plate. Statistically significant differences between the 2 groups were observed for the medial–lateral body sway frequency in parallel stance on a stable and unstable support surface and for the sitting balance task in medial-lateral body sway parameters. Medium to high correlations were observed between body sway during sitting and the parallel stance, as well as between the tandem and single-legged stances. Following microdiscectomy, deficits in postural balance were side specific, as expected by the nature of the pathology. In addition, the results of this study confirmed the connection between proximal balance control deficits and balance during upright quiet balance tasks.

Flutter control of incompressible flow turbomachine blade rows by splitter blades

1994 ◽  
Vol 4 (4) ◽  
pp. 783-804 ◽  
Author(s):  
Hsiao-Wei D. Chiang ◽  
Sanford Fleeter
Keyword(s):  
Incompressible Flow ◽  
Turbomachine Blade
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