High-fidelity numerical study on the effect of riblets on the aerodynamic performance of flat plates
In this student research project, the methods of aerodynamic improvement of a wide variety of aircrafts, with the main objective of reducing drag force, are examined. Different ways of drag reduction are analyzed but an in-depth and further study is made on the methodology of riblet films. Firstly,...
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Γλώσσα: | English |
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2022
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Διαθέσιμο Online: | https://nemertes.library.upatras.gr/handle/10889/23364 |
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"Riblets" "Μη επανδρωμένα αεροσκάφη" Unmanned aerial vehicles Drag reduction Aerodynamic analysis Μείωση οπισθέλκουσας Αεροδυναμική ανάλυση |
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"Riblets" "Μη επανδρωμένα αεροσκάφη" Unmanned aerial vehicles Drag reduction Aerodynamic analysis Μείωση οπισθέλκουσας Αεροδυναμική ανάλυση Αργυρού, Στυλιανός High-fidelity numerical study on the effect of riblets on the aerodynamic performance of flat plates |
description |
In this student research project, the methods of aerodynamic improvement of a wide variety of aircrafts, with the main objective of reducing drag force, are examined. Different ways of drag reduction are analyzed but an in-depth and further study is made on the methodology of riblet films.
Firstly, we find the literature and references from experts in the subject, as to the positive impact of riblet films in terms of drag reduction. As we firstly do our research of the riblet films, then the different geometries of riblets are studied, experimental and theoretical results under specific conditions are reported. Also, their installation in the aviation industry and various problems faced by scientists who are called upon to carry out the proper use of riblets are mentioned.
Then the results of the ONERA M6 wing are validated so that we have a first attempt with the computational fluid dynamics programs. Three different meshes were created in terms of their density, but of the same type, in order to compare the numerical results with the experimental ones. From the validation of the wing results we have drawn some useful conclusions for the correct creation of the meshes, which will then be used for the study of riblets.
Subsequently, five different models of riblets on a flat plate are examined, which are placed inside a rectangular duct of fixed dimensions and located on its lower surface. The rectangular duct was chosen because the top surface is a flat surface parallel to the flow as is the bottom surface of the duct, which is the riblets, so a simultaneous comparison of the two surfaces can be made without the need for additional grids.
The models were tested under the same conditions and for the dimensioning of the riblets some parameters were taken from the flight conditions of the Greek Civil Unmanned Aircraft RX-1, HCUAV. In addition, four different speeds were used for each model. From the results we can have a general view of the ideal non-dimensional distance of the riblets s+, as well as the variation of the vortices, created due to the flow, due to the riblets. We also notice a change in the flow velocity along the riblets. |
author2 |
Argyrou, Stylianos |
author_facet |
Argyrou, Stylianos Αργυρού, Στυλιανός |
author |
Αργυρού, Στυλιανός |
author_sort |
Αργυρού, Στυλιανός |
title |
High-fidelity numerical study on the effect of riblets on the aerodynamic performance of flat plates |
title_short |
High-fidelity numerical study on the effect of riblets on the aerodynamic performance of flat plates |
title_full |
High-fidelity numerical study on the effect of riblets on the aerodynamic performance of flat plates |
title_fullStr |
High-fidelity numerical study on the effect of riblets on the aerodynamic performance of flat plates |
title_full_unstemmed |
High-fidelity numerical study on the effect of riblets on the aerodynamic performance of flat plates |
title_sort |
high-fidelity numerical study on the effect of riblets on the aerodynamic performance of flat plates |
publishDate |
2022 |
url |
https://nemertes.library.upatras.gr/handle/10889/23364 |
work_keys_str_mv |
AT argyroustylianos highfidelitynumericalstudyontheeffectofribletsontheaerodynamicperformanceofflatplates AT argyroustylianos arithmētikēprosomoiōsēypsēlēsakribeiastēsepidrasēstōnribletsstēnaerodynamikēapodosēepipedōnplakōn |
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1771297316394762240 |
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nemertes-10889-233642022-10-12T04:15:40Z High-fidelity numerical study on the effect of riblets on the aerodynamic performance of flat plates Αριθμητική προσομοίωση υψηλής ακρίβειας της επίδρασης των riblets στην αεροδυναμική απόδοση επίπεδων πλακών Αργυρού, Στυλιανός Argyrou, Stylianos "Riblets" "Μη επανδρωμένα αεροσκάφη" Unmanned aerial vehicles Drag reduction Aerodynamic analysis Μείωση οπισθέλκουσας Αεροδυναμική ανάλυση In this student research project, the methods of aerodynamic improvement of a wide variety of aircrafts, with the main objective of reducing drag force, are examined. Different ways of drag reduction are analyzed but an in-depth and further study is made on the methodology of riblet films. Firstly, we find the literature and references from experts in the subject, as to the positive impact of riblet films in terms of drag reduction. As we firstly do our research of the riblet films, then the different geometries of riblets are studied, experimental and theoretical results under specific conditions are reported. Also, their installation in the aviation industry and various problems faced by scientists who are called upon to carry out the proper use of riblets are mentioned. Then the results of the ONERA M6 wing are validated so that we have a first attempt with the computational fluid dynamics programs. Three different meshes were created in terms of their density, but of the same type, in order to compare the numerical results with the experimental ones. From the validation of the wing results we have drawn some useful conclusions for the correct creation of the meshes, which will then be used for the study of riblets. Subsequently, five different models of riblets on a flat plate are examined, which are placed inside a rectangular duct of fixed dimensions and located on its lower surface. The rectangular duct was chosen because the top surface is a flat surface parallel to the flow as is the bottom surface of the duct, which is the riblets, so a simultaneous comparison of the two surfaces can be made without the need for additional grids. The models were tested under the same conditions and for the dimensioning of the riblets some parameters were taken from the flight conditions of the Greek Civil Unmanned Aircraft RX-1, HCUAV. In addition, four different speeds were used for each model. From the results we can have a general view of the ideal non-dimensional distance of the riblets s+, as well as the variation of the vortices, created due to the flow, due to the riblets. We also notice a change in the flow velocity along the riblets. Στην παρούσα διπλωματική εργασία εξετάζονται οι μέθοδοι αεροδυναμικής βελτίωσης των αεροσκαφών, με κύριο στόχο την μείωση της δύναμης της οπισθέλκουσας. Αναλύονται διάφοροι τρόποι μειώσεις της οπισθέλκουσας αλλά γίνεται εμβάθυνση και περεταίρω μελέτη στην μεθοδολογία των riblet films. Γίνεται αρχή, με την εξεύρεση της βιβλιογραφίας και αναφορών από ειδικούς στο εν λόγω θέμα ως προς το θετικό αντίκτυπο που έχουν τα riblet films αναφορικά με τη μείωση της οπισθέλκουσας. Αφού πρώτα εξερευνήσουμε τα riblets και δούμε το υπόβαθρο τους, μελετώνται οι διάφορες γεωμετρίες των riblets, αναφέρονται πειραματικά και θεωρητικά αποτελέσματα σε συγκεκριμένες συνθήκες. Επίσης, αναφέρετε η εγκατάσταση τους στην αεροπορική βιομηχανία αλλά και διάφορα προβλήματα που αντιμετωπίζουν οι επιστήμονες όπου καλούνται να φέρουν εις πέρας για την ορθή χρήση των riblets. Στην συνέχεια γίνεται επικύρωση των αποτελεσμάτων της πτέρυγας ONERA M6 ώστε να έχουμε μια πρώτη επαφή με τα υπολογίστηκα προγράμματα ρευστοδυναμικής. Δημιουργήθηκαν τρία διαφορετικά πλέγματα ως προς την πύκνωση τους, αλλά ίδιου τύπου, με σκοπό να συγκρίνουμε τα αριθμητικά με τα πειραματικά αποτελέσματα. Από την επικύρωση των αποτελεσμάτων της πτέρυγας εξαγάγαμε κάποια χρήσιμα συμπεράσματα για την ορθή δημιουργία των πλεγμάτων που δημιουργήθηκαν για την μετέπειτα μελέτη των riblets. Ακολούθως, εξετάζονται πέντε διαφορετικά μοντέλα riblets σε επίπεδη πλάκα, τα οποία τοποθετήθηκαν μέσα σε ένα ορθογωνικό αγωγό σταθερών διαστάσεων και βρίσκονται στην κάτω επιφάνεια αυτού. Ο ορθογωνικός αγωγός επιλέχθηκε για το λόγο ότι η πάνω επιφάνεια είναι μια επίπεδη επιφάνεια παράλληλη στη ροή όπως επίσης και η κάτω επιφάνεια του αγωγού που είναι τα riblets, έτσι μπορεί να γίνετε ταυτόχρονη σύγκριση των δύο επιφανειών χωρίς να χρειάζονται περεταίρω πλέγματα. Τα μοντέλα ελέγχθηκαν κάτω από τις ίδιες συνθήκες και για την διαστασιολόγηση των riblets πάρθηκαν κάποιες παράμετροι σε συνθήκες πτήσης του Ελληνικού Πολιτικού Μη επανδρωμένου Αεροσκάφους RX-1, HCUAV. Χρησιμοποιήθηκαν τέσσερις διαφορετικές ταχύτητες για το κάθε μοντέλο. Από τα αποτελέσματα που προκύπτουν μπορούμε να έχουμε μια γενική εικόνα για την ιδανική αδιάστατη απόσταση των riblets s+ καθώς και την μεταβολή των δινών, που δημιουργούνται λόγω της ροής, λόγω των riblets. Επίσης, παρατηρούμε να έχουμε μεταβολή στην ταχύτητα της ροής κατά μήκος των riblets. 2022-10-11T10:15:26Z 2022-10-11T10:15:26Z 2022-10-05 https://nemertes.library.upatras.gr/handle/10889/23364 en CC0 1.0 Universal http://creativecommons.org/publicdomain/zero/1.0/ application/pdf |