scholarly journals An Analysis Tool for the Conceptual Design of High-Lift Systems

2021 ◽  
Author(s):  
William J.M. Bissonnette
Keyword(s):  
Conceptual Design ◽  
Analysis Tool ◽  
High Lift ◽  
Induced Drag ◽  
Multiple Data ◽  
Robust Model ◽  
Conceptual Design Phase ◽  
Wake Interactions ◽  
Wake Model ◽  
The Impact

An aerodynamic analysis tool for the conceptual design of high-lift devices has been developed. The method employs a higher-order potential ow method that uses elements of distributed vorticity. The subsequent numerically robust model allows for strong wake interactions, even when using a relaxed wake. The method predicts lift and induced drag values that compare well with multiple data experiments, and, when implemented in a panel code, maximum lift predictions of a high-lift system are found with an error of 6% from experimental data. This method is used to assess the impact that various wake models have on lift and induced drag predictions. This study shows that significant errors can be introduced when employing a prescribed wake model set to extreme angles. Compared to an approach using CFD, the computational expense of these models is relatively low. A single analysis requires minutes, making these models suitable for the iterative conceptual design phase

scholarly journals An Analysis Tool for the Conceptual Design of High-Lift Systems

2021 ◽  
Author(s):  
William J.M. Bissonnette
Keyword(s):  
Conceptual Design ◽  
Analysis Tool ◽  
High Lift ◽  
Induced Drag ◽  
Multiple Data ◽  
Robust Model ◽  
Conceptual Design Phase ◽  
Wake Interactions ◽  
Wake Model ◽  
The Impact

An aerodynamic analysis tool for the conceptual design of high-lift devices has been developed. The method employs a higher-order potential ow method that uses elements of distributed vorticity. The subsequent numerically robust model allows for strong wake interactions, even when using a relaxed wake. The method predicts lift and induced drag values that compare well with multiple data experiments, and, when implemented in a panel code, maximum lift predictions of a high-lift system are found with an error of 6% from experimental data. This method is used to assess the impact that various wake models have on lift and induced drag predictions. This study shows that significant errors can be introduced when employing a prescribed wake model set to extreme angles. Compared to an approach using CFD, the computational expense of these models is relatively low. A single analysis requires minutes, making these models suitable for the iterative conceptual design phase

scholarly journals A Technique to Capture Multi-Disciplinary Tacit Knowledge During the Conceptual Design Phase of a Building Project

2014 ◽  
Vol 13 (02) ◽  
pp. 1450013 ◽  
Author(s):  
Zohreh Pourzolfaghar ◽  
Rahinah Ibrahim ◽  
Rusli Abdullah ◽  
Nor Mariah Adam
Keyword(s):  
Tacit Knowledge ◽  
Conceptual Design ◽  
Explicit Knowledge ◽  
Knowledge Flow ◽  
Design Phase ◽  
Operating Characteristics ◽  
Building Projects ◽  
Incomplete Knowledge ◽  
Conceptual Design Phase ◽  
The Impact

The construction industry is suffering from incomplete knowledge flow that results in time and cost over-runs. Many researchers believe that a large part of this problem is related to the design phase being a tacit knowledge-dominated area. Since tacitness of knowledge contributes to incomplete flow of knowledge, we posit that facilitating the conversion of tacit knowledge to explicit knowledge can improve the overall knowledge flow. Within this context, this paper analyses recognised knowledge-capturing techniques and compares them in view of the operating characteristics of the conceptual design phase. This paper proposes a new tacit knowledge-capturing technique for this phase. The outcomes include a new knowledge-capturing technique, a method for validation of the proposed technique, and recommendations on how to deal with the challenges concomitant with the application and utilisation of the proposed technique in the building industry. By proposing a combinational tacit knowledge-capturing technique, this study attempts to mitigate the impact of the potential incomplete knowledge flow during the conceptual design phase in building projects.

A New Analytical Model of a Centrifugal Compressor and Validation by Experiments

2010 ◽  
Vol 26 (1) ◽  
pp. 37-45 ◽  
Author(s):  
H. Pourfarzaneh ◽  
A. Hajilouy-Benisi ◽  
M. Farshchi
Keyword(s):  
Conceptual Design ◽  
Centrifugal Compressor ◽  
Experimental Studies ◽  
Design Tool ◽  
Operating Conditions ◽  
Experimental Results ◽  
Design Phase ◽  
Robust Model ◽  
Conceptual Design Phase ◽  
Wide Range

AbstractIn the conceptual design phase of a turbocharger, where emphasis is mainly on parametric studies, before manufacturing and tests, a generalized and robust model that implies over a wide range properly, is unavoidable. The critical inputs such as compressor maps are not available during the conceptual design phase. Hence, generalized compressor models use alternate methods that work without any supplementary tests and can operate on wide range. One of the common and applicable modeling methods in design process is the ‘Dimensionless Modeling’ using the constant coefficient scaling (CCS). This method almost can predict the compressor characteristics at design point. However, at off design conditions, error goes up as mass flow and speed parameters increase. Therefore, the results are not reliable at these points. In this paper, a variable coefficient scaling (VCS) method is described. Then, a centrifugal compressor is modeled using the VCS method. To evaluate the model and compare it with the experimental results, some supplementary experiments are performed. Experimental studies are carried out on the compressor of a S2B model of the Schwitzer turbocharger in the turbocharger Lab., at Sharif University of Technology. The comparison between the experimental results and those obtained by the VCS method indicates a good agreement. It also suggests that the present model can be used as an effective design tool for all operating conditions.

scholarly journals Effects of wake shapes on high-lift system aerodynamic predictions

2021 ◽  
Author(s):  
William Bissonnette ◽  
Götz Bramesfeld
Keyword(s):  
Potential Flow ◽  
Numerical Stability ◽  
Aerodynamic Performance ◽  
Design Stage ◽  
Aerodynamic Load ◽  
High Lift ◽  
Induced Drag ◽  
Predicting Performance ◽  
Wake Model ◽  
Stability Issues

High-lift devices are commonly modelled using potential flow methods at the conceptual design stage. Often, these analyses require the use of prescribed wake shapes in order to avoid numerical stability issues. The wake type used, however, has an impact on the absolute aerodynamic load predictions, which is why, in general, these methods are used to assess performance changes due to configuration variations. Therefore, a study was completed that compared the predicted aerodynamic performance changes of such variations of high-lift configurations using different wake types. Lift and induced drag results are compared with the results that were obtained using relaxed wakes and various prescribed wake shapes. Specific attention is given to predictions of performance changes due to changes in geometry. It was found that models with wakes that are prescribed below the freestream direction yield the best results when investigating performance changes due to flap deflections and flap-span changes. The effect of flap-gap sizes is best evaluated using a fully-relaxed model. The numerically most stable approach of wakes that are prescribed leaving the trailing edge upwards seems to be least reliable in predicting performance changes. Keywords: potential flow; wake model; high-lift

Conceptual design and sizing of airframe panels according to safe-life acoustic fatigue criteria

2011 ◽  
Vol 115 (1163) ◽  
pp. 15-27 ◽  
Author(s):  
R. M. Ajaj ◽  
G. Allegri ◽  
A. T. Isikveren
Keyword(s):  
Conceptual Design ◽  
Design Stage ◽  
Skin Thickness ◽  
Analysis Tool ◽  
Reinforced Plastics ◽  
Safe Life ◽  
Sonic Fatigue ◽  
The Impact ◽  
Acoustic Fatigue ◽  
Fatigue Endurance

Abstract This paper presents a methodology that permits accounting for acoustic fatigue effects when sizing safe-life structural skin-stringer panels at the conceptual design stage of aircraft product development. The approach is based upon estimation of the maximum noise radiated from an entry-into-service year 2020 turbofan. Sonic fatigue endurance is assessed for different skin-stringer panels having different values of skin thickness, rib pitch and stringer pitch. Three different materials were considered in this study: aluminium 2024-T3 alloys (Al 2024-T3); carbon fibre-reinforced plastics (CFRP); and, glass reinforced fibre metal laminate (Hybrid Glare-3). The study resulted in CFRP having the most favourable sonic fatigue performance. In order to link economic considerations into technical decision making, the sonic endurance methods were coupled with an industry grade costing analysis tool (SEER-HTM) to examine the impact of safe-life design on the panel cost and weight. The presented methodology has been shown to be sufficiently generic in nature and robust. This will not only assist in identifying acoustic fatigue as a potential critical design scenario, but will also increase throughput during conceptual design sizing and optimisation.

scholarly journals Effects of wake shapes on high-lift system aerodynamic predictions

2021 ◽  
Author(s):  
William Bissonnette ◽  
Götz Bramesfeld
Keyword(s):  
Potential Flow ◽  
Numerical Stability ◽  
Aerodynamic Performance ◽  
Design Stage ◽  
Aerodynamic Load ◽  
High Lift ◽  
Induced Drag ◽  
Predicting Performance ◽  
Wake Model ◽  
Stability Issues

High-lift devices are commonly modelled using potential flow methods at the conceptual design stage. Often, these analyses require the use of prescribed wake shapes in order to avoid numerical stability issues. The wake type used, however, has an impact on the absolute aerodynamic load predictions, which is why, in general, these methods are used to assess performance changes due to configuration variations. Therefore, a study was completed that compared the predicted aerodynamic performance changes of such variations of high-lift configurations using different wake types. Lift and induced drag results are compared with the results that were obtained using relaxed wakes and various prescribed wake shapes. Specific attention is given to predictions of performance changes due to changes in geometry. It was found that models with wakes that are prescribed below the freestream direction yield the best results when investigating performance changes due to flap deflections and flap-span changes. The effect of flap-gap sizes is best evaluated using a fully-relaxed model. The numerically most stable approach of wakes that are prescribed leaving the trailing edge upwards seems to be least reliable in predicting performance changes. Keywords: potential flow; wake model; high-lift

PENGARUH KUALITAS PELAYANAN DAN KEPERCAYAAN TERHADAP LOYALITAS NASABAH PT BANK MANDIRI,Tbk CABANG JAKARTA KELAPA GADING BARAT

2015 ◽  
Vol 3 (3) ◽  
Author(s):  
Imam Wibowo ◽  
Santi Putri Ananda
Keyword(s):  
Linear Regression ◽  
Service Quality ◽  
Multiple Linear Regression ◽  
Analysis Tool ◽  
Positive Contribution ◽  
Homogeneous Population ◽  
Independent Variables ◽  
Research Population ◽  
The Impact

Purpose-To study the impact of the service quality and trust on customers loyalty of PT.Bank Mandiri,Tbk; Kelapa Gading Barat Branch. To improve the customers loyalty there are several factors that can influence them, such as service quality and trust. Methodology/approach-The research population was all customers PT.Bank Mandiri,Tbk;Kelapa Gading Barat Branch.According to the homogeneous population and based on the Gay and Diehl Theory, the samples taken were 50 people. Variables in this investigations consisted of: a).Independent Variables (exogenous): Service Quality (X1) and Trust (X2). b).The dependent variable (endogenous) Customers Loyalty (Y). Analysis tool being used is multiple linear regression which previously conducted validity and realiability. Findings-The result of investigations that service quality and trust simultaneously have a very strong contribution of 75,5% to the customers loyalty, and partially showed that service quality has significant and positive contribution to the customers loyalty of 64,8%. Partially, the trust variable has significant and positive contribution which amounted to 55,9% to the customers loyalty.

scholarly journals Numerical analysis of high-lift configurations with oscillating flaps

2021 ◽  
Author(s):  
Johannes Ruhland ◽  
Christian Breitsamter
Keyword(s):  
Reynolds Number ◽  
Flow Separation ◽  
Separated Flow ◽  
Navier Stokes ◽  
Rotational Axis ◽  
High Lift ◽  
Hinge Point ◽  
Reduced Frequency ◽  
Flap Deflection ◽  
The Impact

AbstractThis study presents two-dimensional aerodynamic investigations of various high-lift configuration settings concerning the deflection angles of droop nose, spoiler and flap in the context of enhancing the high-lift performance by dynamic flap movement. The investigations highlight the impact of a periodically oscillating trailing edge flap on lift, drag and flow separation of the high-lift configuration by numerical simulations. The computations are conducted with regard to the variation of the parameters reduced frequency and the position of the rotational axis. The numerical flow simulations are conducted on a block-structured grid using Reynolds Averaged Navier Stokes simulations employing the shear stress transport $$k-\omega $$ k - ω turbulence model. The feature Dynamic Mesh Motion implements the motion of the oscillating flap. Regarding low-speed wind tunnel testing for a Reynolds number of $$0.5 \times 10^{6}$$ 0.5 × 10 6 the flap movement around a dropped hinge point, which is located outside the flap, offers benefits with regard to additional lift and delayed flow separation at the flap compared to a flap movement around a hinge point, which is located at 15 % of the flap chord length. Flow separation can be suppressed beyond the maximum static flap deflection angle. By means of an oscillating flap around the dropped hinge point, it is possible to reattach a separated flow at the flap and to keep it attached further on. For a Reynolds number of $$20 \times 10^6$$ 20 × 10 6 , reflecting full scale flight conditions, additional lift is generated for both rotational axis positions.

scholarly journals Impact of Dataset Size on Classification Performance: An Empirical Evaluation in the Medical Domain

2021 ◽  
Vol 11 (2) ◽  
pp. 796
Author(s):  
Alhanoof Althnian ◽  
Duaa AlSaeed ◽  
Heyam Al-Baity ◽  
Amani Samha ◽  
Alanoud Bin Dris ◽  
...  
Keyword(s):  
Empirical Evaluation ◽  
Classification Performance ◽  
Support Vector ◽  
Robust Model ◽  
Original Distribution ◽  
C4.5 Decision Tree ◽  
Dataset Size ◽  
Overall Performance ◽  
Medical Domain ◽  
The Impact

Dataset size is considered a major concern in the medical domain, where lack of data is a common occurrence. This study aims to investigate the impact of dataset size on the overall performance of supervised classification models. We examined the performance of six widely-used models in the medical field, including support vector machine (SVM), neural networks (NN), C4.5 decision tree (DT), random forest (RF), adaboost (AB), and naïve Bayes (NB) on eighteen small medical UCI datasets. We further implemented three dataset size reduction scenarios on two large datasets and analyze the performance of the models when trained on each resulting dataset with respect to accuracy, precision, recall, f-score, specificity, and area under the ROC curve (AUC). Our results indicated that the overall performance of classifiers depend on how much a dataset represents the original distribution rather than its size. Moreover, we found that the most robust model for limited medical data is AB and NB, followed by SVM, and then RF and NN, while the least robust model is DT. Furthermore, an interesting observation is that a robust machine learning model to limited dataset does not necessary imply that it provides the best performance compared to other models.

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