Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "tip vortex" wg kryterium: Wszystkie pola

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-10 z 10
    Tytuł:
    Experimental study on dynamic structure of propeller tip vortex
    Autorzy:
    Li, Guangnian
    Chen, Qingren
    Liu, Yue
    Powiązania:
    https://bibliotekanauki.pl/articles/260305.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    propeller
    blade tip
    tip vortex
    PIV
    Opis:
    Propeller cavitation is a main source of fluctuating pressure and noise induced by propellers, and the tip vortex cavitation is the principal source. The present study measures the flow fields near the blade tip using the 2D-PIV technique. The experimental setup and scheme are introduced. We monitor the process of generation and shedding of the propeller tip vortex in real time and analyse the dynamic structure of the tip vortex by testing the propeller wake field under different phases of the axial plane. The distribution characteristics of radial and axial velocity are also analysed. The influence range and the vorticity of the tip vortex and trailing vortex are obtained. All of the measured quantitative data are useful for future propeller design.
    Źródło:
    Polish Maritime Research; 2020, 2; 11-18
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Experimental and Numerical Study of Tip Vortex Cavitation
    Autorzy:
    Szantyr, J. A.
    Flaszyński, P.
    Suchecki, W.
    Alabrudziński, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/260059.pdf
    Data publikacji:
    2011
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    rotary hydraulic machinery
    cavitation
    numerical methods
    experimental techniques
    Opis:
    The article presents the results of the research project concerning tip vortex cavitation. This form of cavitation is very important in operation of many types of rotary hydraulic machines, including pumps, turbines and marine propellers. Tip vortex cavitation generates noise, vibration and erosion. It should be eliminated or significantly limited during the design of these types of machines. The objective of the project was to develop an accurate and reliable method for numerical prediction of tip vortex cavitation, which could serve this purpose. The project consisted of the laboratory experiments and numerical calculations. Inthe laboratory experiments tip vortex cavitation was generated behind a hydrofoil in the cavitation tunneland the velocity field around the cavitating kernel was measured using the Particle Image Velocimetry method. Measurements were conducted in three cross-sections of the cavitating tip vortex for a number ofangles of attack of the hydrofoil and for several values of the cavitation index. In the course of numerical calculations two commercial CFD codes were used: Fluent and CFX. Several available approaches to numerical modeling of tip vortex cavitation were applied and tested, attempting to reproduce the experimental conditions. The results of calculations were compared with the collected experimental data. The most promising computational approach was identified. Keywords:
    Źródło:
    Polish Maritime Research; 2011, 4; 14-22
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dynamic interaction of the cavitating propeller tip vortex with the rudder
    Autorzy:
    Szantyr, J. A.
    Powiązania:
    https://bibliotekanauki.pl/articles/260364.pdf
    Data publikacji:
    2007
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    propeller blades
    rudder
    cavitating
    tip vortex shed
    Opis:
    The hydrodynamic interaction between the ship propeller and the rudder has many aspects. One of the most interesting is the interaction between the cavitating tip vortex shed from the propeller blades and the rudder. This interaction leads to strongly dynamic behaviour of the cavitating vortex, which in turn generates unusually high pressure pulses in its vicinity. Possibly accurate prediction of these pulses is one of the most important problems in the hydrodynamic design of a new ship. The paper presents a relatively simple computational model of the propeller cavitating tip vortex behaviour close to the rudder leading edge. The model is based on the traditional Rankine vortex and on the potential solution of the dynamics of the cylindrical sections of the cavitating kernel passing through the strongly variable pressure field in the vicinity of the rudder leading edge. The model reproduces numerically the experimentally observed process of initial compression of the vortex kernel in the high pressure region near the stagnation point at the rudder leading edge and subsequent explosive growth of the kernel in the low pressure region further downstream. Numerical simulation of this process enables computation of the additional pressure pulses generated due to this phenomenon and transmitted onto the hull surface. This new numerical model of the cavitating tip vortex is incorporated in the modified unsteady lifting surface program for prediction of propeller cavitation, which has been successfully used in the process of propeller design for several years and which recently has been extended to include the effects of propeller – rudder interaction. The results of calculations are compared with the experimental measurements and they demonstrate reasonable agreement between theory and physical reality.
    Źródło:
    Polish Maritime Research; 2007, 4; 10-14
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical prediction of steady and unsteady tip vortex cavitation on hydrofoils
    Autorzy:
    Flaszyński, P.
    Szantyr, J. A.
    Tesch, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/259131.pdf
    Data publikacji:
    2012
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    rotary hydraulic machinery
    vortex cavitation
    numerical methods
    Opis:
    The article presents the numerical method for prediction of tip vortex cavitation generated on hydrofoils. This method has been developed in the course of numerical and experimental research described in earlier publications. The objective of the research was to design the optimum discrete grid structure for this specific computational task and to select the best turbulence model for such an application The article includes a short description of the method and a computational example demonstrating its performance. In this example the results of numerical prediction of the cavitating tip vortex obtained from two commercial CFD codes are compared with experimental photographs taken in the cavitation tunnel in the corresponding flow conditions. Altogether nine different flow conditions are tested and analyzed, but only selected results are included. The accuracy of the numerical predictions is discussed and the reasons for minor existing discrepancies are identified. The unsteady tip vortex calculations are also presented, showing the fluctuations of the transverse velocity components predicted for three cross-sections of the cavitating vortex kernel.
    Źródło:
    Polish Maritime Research; 2012, 3; 3-15
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical analysis of the tip vortex in an air-conditioners propeller fan
    Autorzy:
    Wang, J.
    Wu, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1955218.pdf
    Data publikacji:
    2006
    Wydawca:
    Politechnika Gdańska
    Tematy:
    tip vortex
    internal flow field
    propeller fan
    numerical simulation
    Opis:
    A steady, incompressible, turbulent flow field inside a propeller fan used in an air conditioner has been analyzed numerically using the single-equation Spalart-Allmaras turbulence model. It has been found that the formation of tip vortex starts from the blade tip's suction side at about one third of the axial chord's length aft of the rotor's leading edge. It is due to the rolling-up of the intense shear layer flow between the main axial flow and the suck-in inward flow caused by the large pressure difference between the pressure and the suction sides. The tip vortex passes through the blade passage in a curve reversed towards the direction of the blade's rotation. Its trace is partial to the tangential direction as it goes into the aft part of the blade passage covered by the shroud and, simultaneously, its trace in the radial direction is turned from the outward direction to the inward direction. The operating flow rates have an important effect on the axial position of the tip vor-tex's trace, while its effect on the radial position is negligible. At law flow rates, the vortex disappears at a location closer to the leading edge. The effect of the shroud's width on the tip vortex's trajectory is notable. For a fan with a wide shroud, the trace of the tip vortex moves upstream with a smaller radial influence region than that of a fan with a narrower shroud.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2006, 10, 2; 101-112
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effects of boundary layer control method on hydrodynamic characteristics and tip vortex creation of a hydrofoil
    Autorzy:
    Ghadimi, P.
    Araz-Tanha, A.
    Nemati-Kourabbasloo, N.
    Tavakoli, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/259965.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    steady water injection
    boundary layer control
    hydrofoil
    NACA 0015
    tip vortex
    Opis:
    There is currently a significant focus on using boundary layer control (BLC) approach for controlling the flow around bodies, especially the foil sections. In marine engineering this is done with the hope of increasing the lift – to – drag ratio and efficiency of the hydrofoils. In this paper, effects of the method on hydrodynamic characteristics and tip vortex formation of a hydrofoil are studied. Steady water injection at the tip of the hydrofoil is simulated in different conditions by using ANSYS-CFX commercial software. Validity of the proposed simulations is verified by comparing the obtained results against available experimental data. Effects of the injection on the lift, drag, and lift – to – drag ratio are studied and the ranges within which the injection has the most positive or negative effects, are determined. Furthermore, flow pattern and pressure variation are studied upon the water injection to determine the most positive and negative case and to ascertain the main reasons triggering these phenomena.
    Źródło:
    Polish Maritime Research; 2017, 2; 27-39
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Eksperymentalne pomiary geometrii kawitującego jądra wiru oraz pola prędkości w jego otoczeniu
    Experimental method for measurements of cavitating tip vortex geometry and surrounding liquid velocity field
    Autorzy:
    Suchecki, W.
    Alabrudziński, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2072104.pdf
    Data publikacji:
    2013
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    kawitacja
    wizualizacja przepływów
    metoda DPIV
    cavitation
    flow visualisation
    DPIV method
    Opis:
    W pracy przedstawiono eksperymentalną metodę pomiaru kawitującego jądra wiru generowanego przez model płata przy dużych prędkościach względnych. Przeprowadzone badania eksperymentalne polegały na rejestracji fotograficznej geometrii wiru generowanego przez model płata w tunelu kawitacyjnym oraz na pomiarach pola prędkości przepływu w sąsiedztwie kawitującego jądra wirowego metodą DPIV. Układ pomiarowy obejmował laser New Wave 120XT-15Hz, dual-Nd:YAG oraz kamerę pco.l200hs z synchronizerem ILA. Zastosowana w pracy tzw. maska kalibracji, pozwoliła na usunięcie zniekształceń obrazu, jednak nie pozwoliła na jednoznaczne określenie położenia obszaru pomiarowego względem ścian kanału. Stwierdzono przydatność zastosowanych metod wizualizacyjnych do badania przepływów, w których występuje kawitacja.
    The paper presents the experimental method for measurements of cavitating tip vortex generated by the hydrofoil model at high relative velocities. The experimental procedure included the image acquisition of cavitating tip vortex geometry and DPIV measurements of surrounding liquid velocity field. The measuring system included the New Wave 120XT-15Hz laser, dual- Nd: YAG laser and the camera pco,1200hs with Synchronizer ILA. The socalled calibration mask used during experiments made it possible to remove the image distortion, however, did not allow for the clear identification of the measurement area position with respect to canal walls. The usefulness of applied methods in the study of flow visualization in the presence of cavitation was demonstrated.
    Źródło:
    Inżynieria i Aparatura Chemiczna; 2013, 6; 563--565
    0368-0827
    Pojawia się w:
    Inżynieria i Aparatura Chemiczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A method for the accurate numerical prediction of the tip vortices shed from hydrofoils
    Autorzy:
    Flaszyński, P.
    Szantyr, J. A.
    Dymarski, P.
    Kraskowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/259231.pdf
    Data publikacji:
    2010
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    marine propulsors
    vortex generation
    numerical methods
    experimental techniques
    Opis:
    The possibly accurate numerical prediction of the detailed structure of vortices shed from the tips of hydrofoils is an important element of the design process of marine propellers. The concentrated tip vortices are responsible for the propeller cavitation erosion and acoustic emission. The purpose of the project described in this paper was to develop the numerical method for prediction of the tip vortex structure. In the course of the project the numerical calculations were confronted with the results of experimental measurements. This led to creation of the specific method of construction of the computational grid and to selection of the optimum turbulence model. As a result the reliable method for the accurate numerical prediction of the concentrated tip vortices for different hydrofoil geometry and flow conditions has been developed and validated. This method enables elimination of the unfavourable phenomena related to the tip vortices in the course of the propeller design calculations.
    Źródło:
    Polish Maritime Research; 2010, 2; 10-17
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical analysis on the influence of the twisted blade on the aerodynamic performance of turbine
    Autorzy:
    Jin, J.
    Wang, Z.
    Cao, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/258444.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    turbine
    twisted blade
    leakage vortex
    pressure gradient
    tip clearance
    Opis:
    With the gradual increase of the thermal power unit capacity, the inlet steam parameters and flow of the turbine also increase gradually, which causes considerable secondary flow loss. Therefore, studying the causes and distribution of secondary flow loss within the level is of great significance to effectively improve the stage internal efficiency of turbine. Take high-pressure stage moving blade of a turbine as the research object, and adopt the k-ωSST model, the SIMPLEC algorithm to numerically simulate the formation and development process of leakage vortex between the tip clearance of the positive bending twisted blade and its effect on the secondary flow of cascade passage. Results show that relative to the conventional twisted blade, the scope of influence of leakage vortex which the steam flow formed near the suction surface of positive bending twisted blade and the disturbance to passage mainstream become smaller, and the increase of tip clearance has weakened the „C” type pressure gradient of suction surface of the positive bending twisted blade, increased the thickness of the boundary layer at both ends of blades and the loss of the blade end.
    Źródło:
    Polish Maritime Research; 2016, S 1; 86-90
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of topology and vortex structure in turbine cascades with tip clearance under different incidence angles
    Badania topologii i struktury wirów palisady turbiny z luzem wierzchołkowym przy różnych kątach natarcia
    Autorzy:
    Yan, P. G.
    Qiang, X. Q.
    Teng, J. F.
    Han, W. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/279519.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    turbine cascade
    tip clearance
    topological rules
    experimental study
    Opis:
    Three sets of conventional straight, positive curved and negative curved turbine cascades with tip clearance were tested with experimental measurement. The impact of incidence angles and blade bending on the tip leakage was studied under larger clearance (0.036 of span). An ink trace visualization of the wall flow and topology theory was adopted and thus the topological structures of the blade surface, the upper and lower end wall were analyzed in this paper. It was found that, compared with the same cascade under the zero incidence angle, the saddle points all move to the upstream, the scope of the separation expands along the flow and span direction, and the separation line of the upper and lower passage vortex climb to the middle span of the blade when the flow incidence angle increased from zero to 20º. Under the condition of zero and 20º incidence angle, the positive curved blade will eliminate the upper passage vortex. The numbers of singular points are reduced and the interaction loss between the passage vortex and the leakage vortex is greatly reduced too. On the other hand, it also strengthens the blocking effect of the end wall cross flow on the leakage flow, thereby reduces the relative leakage flow rate.
    W pracy zaprezentowano wyniki pomiarów eksperymentalnych trzech zestawów konwencjonalnych palisad turbin o prostym, dodatnio i ujemnie zakrzywionym profilu. Zbadano wpływ kąta natarcia oraz efekt zginania łopatek na straty wskutek upływu przy luzie wierzchołkowym sięgającym 3.6% rozpiętości łopatek. Do analizy zastosowano wizualizację śladów pozostawianych barwnikiem oraz teorię topologii, tj. struktur topologicznych reprezentujących powierzchnię łopatki oraz górnej i dolnej ściany krańcowej. Zaobserwowano, że w porównaniu do analogicznej palisady o zerowym kącie natarcia wszystkie punkty siodłowe przesuwają się w gorę przepływu, a obszar oderwania strugi rozszerza się wzdłuż promienia łopatki. Jednocześnie granica oderwania górnego i dolnego wiru przemieszcza się ku środkowi łopatki, gdy kąt natarcia narasta od zera do 20◦. Przy tych granicznych wartościach kąta natarcia łopatki o dodatniej krzywiźnie profilu eliminują górny wir podczas przejścia. Ponadto okazało się, że liczba punktów osobliwych zmniejszyła się podobnie, jak osłabiła się interakcja pomiędzy wirami przejścia i wirami upływu. Stwierdzono, że wzmacnia to efekt blokowania upływu poprzecznym przepływem na krańcowej ścianie łopatki, co ostatecznie redukuje straty indukowane upływem.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2013, 51, 2; 363-373
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-10 z 10

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies