2/98 "Computational Fluid Dynamics"
Guest editor: prof. Tadeusz Chmielniak,
Silesian Technical University, Poland
Contents:
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Z.Kazimierski, Short Review of the CFD Activities in Poland
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T.Chmielniak, Computational Fluid Dynamics Methods in Turbomachinery
- abstract
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F.Magagnato, Karlsruhe Parallel Program for Aerodynamics - KAPPA
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P.Doerffer, J.Kaczynski, Transonic flows, shock wave turbulent - boundary
interaction - abstract
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T.Chmielniak, W.Wroblewski, Numerical Simulation of the Balde Cascade
Flows Using Upwind Methods - abstract
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S.Yershov, A.Rusanov, A.Gardzilewicz, P.Lampart, J.Swirydczuk, Numerical
simulation of 3D flow in axial turbomachines - abstract
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T.J.Bugalski, J.Szantyr, Application of CFD for Analysis of the Ship
and Propeller Flow - abstract
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J.Piechna, A.P.Szumowski, Numerical Study of the Parallel Vortex-Airfoil
Interaction - abstract
From the History of Science and Technology in Ancient Gdansk
Abstracts:
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T.Chmielniak, Computational Fluid Dynamics Methods
in Turbomachinery
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This paper aims to present a general view of the flow problems in turbomachinery
and the current levels of numerical methods for solving these problems.
The flow models used for modelling phenomena in blade cascade are presented.
The models of turbulence are discussed. A variety of examples of turbomachinery
problems, such as steady, unsteady flows, multiphase and multicomponent
flows, blade cooling are described. The actual research fields of computational
fluid mechanics are presented.
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P.Doerffer, J.Kaczynski, Transonic flows, shock
wave turbulent - boundary interaction
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Shock wave - boundary layer interaction is one of the most important phenomenon
in transonic flows. Due to its complexity it is difficult as well for experimental
as for numerical study. The growing potential of the CFD is therefore of
high importance.
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The different aspects of shock wave - boundary layer interaction should
be studied in different flow configurations. Therefore results concerning
profile flow, helicopter rotor at hovering and forward flight and internal
flows are presented in this paper. These are to illustrate our ability
in CFD in general. Besides the flows simulation the work directed to a
development of used codes is carried out.
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T.Chmielniak, W.Wroblewski, Numerical Simulation
of the Balde Cascade Flows Using Upwind Methods
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In this paper a mathematical formulation of the equations of the fluid
motion in turbomachinery cascades has been presented. Some review of the
calculation methods for solving these equations is given. These methods
are based on an explicit time marching scheme with finite volume discretisation
and upwind-biased technique for the inviscid fluxes calculations. The high
order accuracy in space is realized by the MUSCL approximation. The discretisations
methods and numerical grids are described. The calculations of viscous
and inviscid flow models are performed. The model and results of
the water steam flow analysis with homogeneous condensation are presented.
The calculations are performed for complex problems of real blade configurations
of turbomachinery.
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S.Yershov, A.Rusanov, A.Gardzilewicz, P.Lampart, J.Swirydczuk,
Numerical simulation of 3D flow in axial turbomachines
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The paper is intended to describe a method for the calculation of 3D viscous
compressible (subsonic or supersonic) flow in axial turbomachines described
in the form of thin-layer Reynolds-averaged Navier-Stokes equations. The
method draws on Godunov-type upwind differencing and ENO reconstruction
suggested by Harten, so as to assure monotonicity preserving and high accuracy
of computational results. The computational efficiency is achieved thanks
to the implementation of a simplified H-type multi-grid approach and *-form
implicit step. Turbulent effects are simulated with the help of a modified
algebraic model of Baldwin-Lomax. This method was at the foundation of
a computer code - a complex software package to calculate 3D flow in multi-stage
turbomachines that allows us to obtain local characteristics, like temperature,
pressure, density or velocity distributions, as well as global characteristics,
like flow rates, stage reaction, flow efficiency for the considered turbine/compressor
stage. The paper also gives selected results of computation of a number
of turbimachinery cascades, showing that these results agree reasonably
well with the available experimental data.
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T.J.Bugalski, J.Szantyr, Application of CFD for
Analysis of the Ship and Propeller Flow
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The paper describes the computer system PANSHIP for analysis of flow around
the ship hull moving with constant velocity in calm water, including the
effects of free surface and propeller operation. This system calculates
the potential flow using the discrete distribution of Rankine sources on
the hull. Viscous flow is computed using integral method in the bow section
and Reynolds Averaged Navier Stokes equation (RANS) in the stern section
of the ship hull. Results of this analysis may be directly used in ship
hull design and they may also serve as input for calculation of the unsteady
flow phenomena accompanying propeller operation in the non-uniform velocity
field generated by the hull. PANSHIP has been verified experimentally and
it forms a useful tool available for ship designers and for marine hydrodynamicists.
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J.Piechna, A.P.Szumowski, Numerical Study of
the Parallel Vortex-Airfoil Interaction
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The effect of a strong vortex interacting with an airfoil flow is investigated
numerically. The finite volume method for Euler equations is applied. Instantanous
flow patterns, including pressure distributions along the airfoil and lift
coefficients, were calculated for various miss distancees of the vortex
passing parallely to the airfoil plane. It has been found that the effects
of interaction are much stronger when the vortex approaching the airfoil
accelerates the flow at the pressure surface than in the case when the
vortex decelerates the flow at the suction surface. The lift coefficient
only slightly depends on the vortex core radius if the velocity induced
at the airfoil surface by vortices of various cores is constant. In contrast
to this the intensity of the acoustic disturbance produced during the interaction
strongly depends on the core radius even for a constant induced flow velocity.
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