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You searched for subject:(pressure signature). Showing records 1 – 3 of 3 total matches.

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Delft University of Technology

1. Kinderman, Hendrik Wisse (author). The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds.

Degree: 2017, Delft University of Technology

This research project aims at obtaining a better understanding of vertically translating the wing and the related wing-body interference effects on the drag and sonic boom. Computational Fluid Dynamics (CFD) analysis using the Euler equations has been used to evaluate an airplane with different vertical wing placements at a lift coefficient of 0.15 at a Mach-number of 1.6 and also in zero-lift conditions. Pressure distributions, drag forces and pressure signatures have been calculated in order to assess the performance in terms of wave drag and sonic booms. These results have been analysed to find out why certain effects are happening for these configurations. The low wing configuration has the highest lift-to-drag ratio due to interference on the upper wing surface close to the fuselage. The lift-to-drag ratio for CL = 0.15 is found to be 4.79% higher compared to the worst performing configuration, the high wing configuration. Due to the local geometry of the low wing configuration it is possible to cre- ate additional suction on the upper wing surface, which positively affects the performance. Pressure signatures are extracted at 1 body-length distance (70푚) from the aircraft for several azimuth angles. These distributions show that the low wing configuration also has the lowest impulse and maximum overpressure. The higher wing configurations show an extra peak in overpressure emanating from the trailing end of the wing, which is created due to interference effects. Below the wing surface there is a large volume of the fuselage, while it is absent for the low wing configuration. Therefore the higher wing configurations show an extra peak in the pressure signature. Next to this discovery, an analysis is presented to relate the geometry of the configurations to the wave drag by assessing the cross-sectional area distribution using different intersection methods. These methods are compared with other methods found in the literature. Two methods which use a single Mach-cone have been analysed, as well as a method incorporating a forward and a backward pointed Mach-cone. One method translates a Mach-cone vertically to align the vertex of the Mach-cone with the centroid of the intersection with the aircraft. This gives an x,z-position which can be used to adjust the area distribution. The drag for the methods using a single Mach-cone was overestimated by a factor of 2, but after multiplying these results by a factor of / the results for the heigh-weighted Mach-cone method approached the wave drag results from CFD within 5%. The double Mach-cone method showed an even better agreement with less variation, while no multiplication factor was applied. A further analysis has taken place to find out why some methods that incorporate a single Mach- cone to evaluate the cross-sectional area to calculate the wave drag, overestimate the drag by a factor of 2. It is found that these methods do not overestimate the drag for a simple shape, such as a Sears- Haack body. The methods simply overestimate the cross-sectional area,… Advisors/Committee Members: Schrijer, Ferdinand (mentor), Delft University of Technology (degree granting institution).

Subjects/Keywords: sonic boom; vertical wing placement; wave drag; drag; supersonic; pressure signature; lift; zero-lift; area ruling; area rule; Mach; cone

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Kinderman, H. W. (. (2017). The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:b5eaa808-6067-46a5-8d45-0e14d18ceeef

Chicago Manual of Style (16th Edition):

Kinderman, Hendrik Wisse (author). “The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds.” 2017. Masters Thesis, Delft University of Technology. Accessed January 19, 2021. http://resolver.tudelft.nl/uuid:b5eaa808-6067-46a5-8d45-0e14d18ceeef.

MLA Handbook (7th Edition):

Kinderman, Hendrik Wisse (author). “The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds.” 2017. Web. 19 Jan 2021.

Vancouver:

Kinderman HW(. The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds. [Internet] [Masters thesis]. Delft University of Technology; 2017. [cited 2021 Jan 19]. Available from: http://resolver.tudelft.nl/uuid:b5eaa808-6067-46a5-8d45-0e14d18ceeef.

Council of Science Editors:

Kinderman HW(. The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds. [Masters Thesis]. Delft University of Technology; 2017. Available from: http://resolver.tudelft.nl/uuid:b5eaa808-6067-46a5-8d45-0e14d18ceeef

2. Sjöholm, Thomas. The Needed Input Data for Accurate On-line Signature Verification : The relevance of pressure and pen inclination for on-line signature verification.

Degree: Computer Science and Communication (CSC), 2015, KTH

Signatures have been used to authenticate documents and transactions for over 1500 years and are still being used today. In this project a method for verifying signatures written on a tablet has been developed and tested in order to test whether pressure information is vital for a well performing on-line signature verification systems. First a background study was conducted to learn about the state-of-the-art methods and what features several research systems used, then the method was developed. The method is a Dynamic Time Warp with 8 local features, 2 of them were pressure values or derived from pressure, and 1 global feature. The developed method was tested on SUSig visual corpus containing signatures from 94 persons. The Equal Error Rate (EER) when not using pressure was 5.39 % for random forgeries and 3.24 % for skilled forgeries. EER when using pressure was 5.19 % for random forgeries and 2.80 % for skilled forgeries. The background study concluded that pen inclination is not required for a well performing system. Considering the result of this project and the result of others, it seems that pressure information is not vital, but provide some valuable information that can be used to classify signatures more accurately.

Signaturer har blivit använda för att autentisera dokument och transaktioner i över 1500 år och används än idag. En metod för att testa signaturer skrivna på en digital platta har utvecklats för att testa huruvida tryckkänslighet och vinkeln på pennan är kritiskt för ett välpresterande on-line signature verification system. Först så genomfördes en bakgrundsstudie för att se hur andra moderna metoder gör och vad för features de använder för att sen utveckla metoden. Den använda metoden är en Dynamic Time Warp med 8 lokala features varav 2 är tyckkänslighet eller utvunna från tryckkänslighet samt en global feature. Metoden testades sedan på SUSig visual corpus som har signaturer från 94 personer. Equal Error Rate (EER) för de feature kombinationerna som inte använde tryckkänslighet blev 5.39 % för slumpmässiga signaturer och 3.24 % för förfalskningar. EER för kombinationer av features som innehåller tryckkänslighet blev 5.19 % för slumpmässiga signaturer och 2.80 % för förfalskningar. Givet resultatet av det här projektet samt andra projekt utforskade i bakgrundsstudien så verkar tryckkänslighet inte vara kritiskt men ger en del värdeful information för klassificera signaturer mer träffsäkert. Bakgrundsstudien gav att vinkeln på pennan inte var kritisk för att välpresterande system.

Subjects/Keywords: Online signature verification; signature verification; dynamic time warp; pressure sensitivity; susig; Sabanci University Signature Database; signaturverifiering; tryckkänslighet; susig; Sabanci University Signature Database; Computer Sciences; Datavetenskap (datalogi)

…velocities, acceleration, pressure and direction of movement are some of the most common features… …x28;Pf , Qf ) (6) f =1 2.2.2 Dynamic Time Warping for On-line Signature… …Verification The sequence in the context of on-line signature verification is the set of features… …signature is compared to either a reference average signature that includes how the different… …Description How well an on-line signature verification system performs can be evaluated in several… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Sjöholm, T. (2015). The Needed Input Data for Accurate On-line Signature Verification : The relevance of pressure and pen inclination for on-line signature verification. (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177879

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Sjöholm, Thomas. “The Needed Input Data for Accurate On-line Signature Verification : The relevance of pressure and pen inclination for on-line signature verification.” 2015. Thesis, KTH. Accessed January 19, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177879.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Sjöholm, Thomas. “The Needed Input Data for Accurate On-line Signature Verification : The relevance of pressure and pen inclination for on-line signature verification.” 2015. Web. 19 Jan 2021.

Vancouver:

Sjöholm T. The Needed Input Data for Accurate On-line Signature Verification : The relevance of pressure and pen inclination for on-line signature verification. [Internet] [Thesis]. KTH; 2015. [cited 2021 Jan 19]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177879.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sjöholm T. The Needed Input Data for Accurate On-line Signature Verification : The relevance of pressure and pen inclination for on-line signature verification. [Thesis]. KTH; 2015. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177879

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

3. Bailey, Matthew Marlando. An Extended Calibration and Validation of a Slotted-Wall Transonic Wall-Interference Correction Method for the National Transonic Facility.

Degree: PhD, Aerospace Engineering, 2019, Virginia Tech

The purpose of conducting experimental tests in wind tunnels is often to acquire a quantitative measure of test article aerodynamic characteristics in such a way that those specific characteristics can be accurately translated into performance characteristics of the real vehicle that the test article intends to simulate. The difficulty in accurately simulating the real flow problem may not be readily apparent, but scientists and engineers have been working to improve this desired equivalence for the better part of the last half-century. The primary aspects of experimental aerodynamics simulation that present difficulty in attaining equivalence are: geometric fidelity, accurate scaling, and accounting for the presence of walls. The problem of scaling has been largely addressed by adequately matching conditions of similarity like compressibility (Mach number), and viscous effects (Reynolds number). However, accounting for the presence of walls in the experimental setup has presented ongoing challenges for ventilated boundaries; these challenges include difficulties in the correction process, but also extend into the determination of correction uncertainties. Exploiting a previously designed statistical validation method, this effort accomplishes the extension of a calibration and validation effort for a boundary pressure wall interference corrections method. The foundational calibration and validation work was based on blockage interference only, while this present work extends the assessment of the method to encompass blockage and lift interference production. The validation method involves the establishment of independent cases that are then compared to rigorously determine the degree to with the correction method can converge free-air solutions for differing interference scenarios. The process involved first establishing an empty-tunnel calibration to gain both a centerline Mach profile of the facility at various ventilation settings, and to gain a baseline wall pressure signature undisturbed by a test article. The wall boundary condition parameters were then calibrated with a blockage and lift interference producing test article, and final corrected performance coefficients were compared for varying test section ventilated configurations to validate the corrections process and assess its domain of applicability. During the validation process discrimination between homogeneous and discrete implementations of the boundary condition was accomplished and final results indicated comparative strength in the discrete implementation's ability to capture experimental flow physics. Final results indicate that a discrete implementation of the General Slotted Wall boundary condition is effective in significantly reducing variations caused by differing interference fields. Corrections performed with the discrete implementation of the boundary condition collapse differing measurements of lift coefficient to within 0.0027, drag coefficient to within 0.0002, and pitching moment coefficient to within 0.0020. Advisors/Committee Members: Devenport, William J. (committeechair), Schetz, Joseph A. (committee member), Lowe, Kevin T. (committee member), Walker, Eric L. (committee member).

Subjects/Keywords: Accuracy; Blockage; Boundary Pressure; Calibration; Lift Interference; Slotted-Wall; Transonic Wind Tunnel Testing; Validation; Ventilated Wall; Wall Interference; Wall Signature

…Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.4.3 Pressure Measurement… …101 7.2 Experimental Wall Signature… …105 7.3 Computational Wall Signature… …7.3.3 Wall Signature Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 7.4… …Wall Signature Residuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Bailey, M. M. (2019). An Extended Calibration and Validation of a Slotted-Wall Transonic Wall-Interference Correction Method for the National Transonic Facility. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/95882

Chicago Manual of Style (16th Edition):

Bailey, Matthew Marlando. “An Extended Calibration and Validation of a Slotted-Wall Transonic Wall-Interference Correction Method for the National Transonic Facility.” 2019. Doctoral Dissertation, Virginia Tech. Accessed January 19, 2021. http://hdl.handle.net/10919/95882.

MLA Handbook (7th Edition):

Bailey, Matthew Marlando. “An Extended Calibration and Validation of a Slotted-Wall Transonic Wall-Interference Correction Method for the National Transonic Facility.” 2019. Web. 19 Jan 2021.

Vancouver:

Bailey MM. An Extended Calibration and Validation of a Slotted-Wall Transonic Wall-Interference Correction Method for the National Transonic Facility. [Internet] [Doctoral dissertation]. Virginia Tech; 2019. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/10919/95882.

Council of Science Editors:

Bailey MM. An Extended Calibration and Validation of a Slotted-Wall Transonic Wall-Interference Correction Method for the National Transonic Facility. [Doctoral Dissertation]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/95882

.