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Wyszukujesz frazę "L/D ratio" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Hole extension effect on transpiration flow efficiency
Autorzy:
Lewandowski, T.
Doerffer, P.
Powiązania:
https://bibliotekanauki.pl/articles/1938639.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska
Tematy:
perforated wall
L/D ratio
mass flow rate
efficiency
Opis:
The present analysis of the hole extension effect on the transpiration flow efficiency is a part of the research [1] which aims at defining a physical transpiration model of the flow through perforated plates. Perforated walls find a wide use as a method of flow control and effusive cooling. Some data on the L/D (hole length to diameter ratio) effect on the flow structure and mass flow rate may be found in the literature [2, 3], but all those works concern holes of a diameter at least one order of magnitude larger than those used in the simulations presented in this paper. Due to the size of the analyzed holes and their cylindrical shape, the only method of analysing the flow through such holes is the numerical method. In the conducted simulations, the holes were D = 0.6 mm, 0.3 mm and 0.125 mm in diameter and the perforation values were equal to 4%, 5%, 8% and 10%. The L/D ratio was changed between 0.25 and 8. The data bank of the flow through the cylindrical holes was produced. The hole extension has a significant influence on the obtained mass flow rate and, consequently, on the transpiration flow efficiency. In addition, entrance effects appear to be important.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2015, 19, 2; 121-128
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape optimization of a hydrofoil with leadingedge protuberances using full factorial sweep sampling and an RBF surrogate model
Autorzy:
Nazemian, Amin
Ghadimi, Parviz
Powiązania:
https://bibliotekanauki.pl/articles/135182.pdf
Data publikacji:
2020
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
humpback whale flippers
leading-edge protuberances
free-form deformation (FFD)
surrogate model
CFD
lift-to-drag ratio (L/D)
Opis:
This paper investigates improving the leading-edge of a hydrofoil with sinusoidal protuberances based on its hydrodynamic performance. The original hydrofoil geometry was inspired by the leading edge of the flipper of a humpback whale. A multi-step optimization process was performed for a 634-021 hydrofoil. The free-form deformation technique defined the shape parameters as a variable design, and these parameters included the amplitude of the leading-edge protuberances, which ranged from 0 to 20% of the chord length, and the corrugate span, with 3 and 4 crests. The flow characteristics of a parametric hydrofoil were examined using a CFD solver, and the lift, drag, and lift-to-drag ratio (L/D) were computed as responses to the optimization cycle. To accomplish this, two design study methods were sequentially applied at different angles of attack. A full factorial design sweep tool was applied that went through all parameter value combinations, and an RBF-based surrogate model was constructed to investigate the system behavior. The results indicated the existence of an optimum design point, and the highest L/D ratio was determined to be 10.726 at a 12° angle of attack.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2020, 62 (134); 116-123
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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