Recent Applications of the FNS Zonal Method to Complex Flow Problems

1991 ◽  
Author(s):  
Kozo Fujii ◽  
Yoshiaki Tamura
Keyword(s):  
Complex Flow ◽  
Zonal Method ◽  
Flow Problems

Coda

2018 ◽  
Author(s):  
Sauro Succi
Keyword(s):  
Fluid Dynamics ◽  
Boltzmann Equation ◽  
Broad Spectrum ◽  
Lattice Boltzmann ◽  
Lattice Boltzmann Equation ◽  
Real Difference ◽  
Complex Flow ◽  
Flow Problems ◽  
Subjective View

This section of the book revisits a question from the book The Lattice Boltzmann Equation (for fluid dynamics and beyond). This question is: What did we learn through lattice Boltzmann? Did LB make a real difference to our understanding of the physics of fluids and flowing matter in general? Here, the text aims to offer a subjective view, without the presumption of being right. Besides being routinely used for a broad spectrum of complex flow problems, there are, in the opinion expressed in this part of the book, a few precious instances in which LB has made a palpable difference.

RANS Maneuvering Simulation of Esso Osaka With Rudder and a Body-Force Propeller

2005 ◽  
Vol 49 (02) ◽  
pp. 98-120
Author(s):  
Claus D. Simonsen ◽  
Frederick Stern
Keyword(s):  
Flow Field ◽  
Open Water ◽  
Verification And Validation ◽  
Fair Agreement ◽  
Navier Stokes ◽  
Complex Flow ◽  
Flow Problems ◽  
The Difference ◽  
Propeller Geometry ◽  
Flow Study

A simplified potential theory-based infinite-bladed propeller model is coupled with the Reynolds averaged Navier-Stokes (RANS) code CFDSHIP-IOWA to give a model that interactively determines propeller-hull-rudder interaction without requiring detailed modeling of the propeller geometry. Computations are performed for an open-water propeller, for the Series 60 ship sailing straight ahead and for the appended tanker Esso Osaka in different maneuvering conditions. The results are compared with experimental data, and the tanker data are further used to study the interaction among the propeller, hull, and rudder. A comparison between calculated and measured data for the Series 60 ship shows fair agreement, where the computation captures the trends in the flow, that is, the flow structure and the magnitude of the field quantities together with the integral quantities. For the tanker, the flow study reveals a rather complex flow field in the stern region, where the velocity distribution and propeller loading reflect the flow field changes caused by the different maneuvering conditions. The integral quantities, that is, the propeller, hull, and rudder forces, are in fair agreement with experiments. No formal verification and validation are performed, so the present results are related to previous work with verification and validation of the same model, but without the propeller. For the validated cases, the levels of validation are the same as without the propeller, because the validation uncertainties, that is, the combined experimental and simulation uncertainties, are assumed to be the same for both cases. Based on this, validation is obtained for approximately the same cases as for the without-propeller conditions, but the comparison errors, that is, the difference between experiment and calculation, are different. For instance, the difference between computation and experiment for the ship resistance is generally larger with the propeller than without, whereas the opposite is the case for the rudder drag. Summarizing the results, the method shows encouraging results, and taking the effort related to modeling the propeller into account, the method appears to be useful in connection with studies of rudder-propeller-hull related flow problems, where the real propeller geometry cannot be modeled.

Methods for parallel computation of complex flow problems

1999 ◽  
Vol 25 (13-14) ◽  
pp. 2039-2066 ◽  
Author(s):  
Tayfun Tezduyar ◽  
Yasuo Osawa
Keyword(s):  
Parallel Computation ◽  
Complex Flow ◽  
Flow Problems

Flows of thin streams with free boundaries

1973 ◽  
Vol 59 (3) ◽  
pp. 417-432 ◽  
Author(s):  
Joseph B. Keller ◽  
James Geer
Keyword(s):  
Channel Flow ◽  
Potential Flow ◽  
Slenderness Ratio ◽  
Asymptotic Series ◽  
Two Dimensional ◽  
Free Boundaries ◽  
Complex Flow ◽  
Flow Problems ◽  
Different Types ◽  
Wall Flow

A method is developed for determining any thin steady two-dimensional potential flow with free and/or rigid boundaries in the presence of gravity. The flow is divided into a number of parts and in each part the flow and its free boundaries are represented as asymptotic series in powers of the slenderness ratio of the stream. There are three basic flows, having two, one and no free boundaries and called jet flow, wall flow and channel flow, respectively. First the three expansions for these flows are found, extending results of Keller & Weitz (1952). They are called outer expansions to distinguish them from the inner expansions which apply near the ends of the stream or at the junction of two different types of flow. The inner and outer expansions must be matched at a junction to find how the emerging flow is related to the entering flow. This process can be continued to build up any complex flow involving thin streams. The method is illustrated in the case of a wall flow that leaves the wall to become a jet, which includes the case of a waterfall treated by Clarke (1965) in a similar way. In part 2 (to be published) other inner expansions are found and matched to outer expansions, providing the ingredients for the construction of the solutions of many flow problems.

An adaptive finite element strategy for complex flow problems

1987 ◽  
Author(s):  
J. ODEN ◽  
T. STROUBOULIS ◽  
PH. DEVLOO ◽  
L. SPRADLEY ◽  
J. PRICE
Keyword(s):  
Finite Element ◽  
Adaptive Finite Element ◽  
Complex Flow ◽  
Flow Problems

Computation of Aeroacoustics and Fluid Flow Problems Using a Novel Dispersion Relation Preserving Scheme

2019 ◽  
Vol 28 (01) ◽  
pp. 1850063 ◽  
Author(s):  
Bikash Mahato ◽  
Ganta Naveen ◽  
Yogesh G. Bhumkar
Keyword(s):  
Fluid Flow ◽  
Dispersion Relation ◽  
Laminar Flow ◽  
Circular Cylinder ◽  
Neutral Stability ◽  
Direct Simulation ◽  
Complex Flow ◽  
Flow Problems ◽  
Accurate Scheme ◽  
Drp Scheme

A new spectrally optimized physical dispersion relation preserving scheme has been introduced to solve computational acoustics and aeroacoustics problems, accurately. The derived fourth-order accurate scheme has significant spectral resolution and physical dispersion relation preserving (DRP) nature. The scheme displays neutral stability at high CFL numbers. The developed scheme has an ability to add numerical diffusion as and when required to attenuate spurious waves present in the computed solutions. These features make the proposed scheme suitable for solving computational aeroacoustic problems. The scheme has been validated by comparing solutions of model computational acoustic problems with the available analytical solutions. Scheme has also been tested to solve the incompressible flow field around a circular cylinder executing rotary oscillations. Ability of the scheme to perform direct simulation of the computational aeroacoustic problems has been shown by computing acoustic field triggered by a laminar flow past a stationary circular cylinder. Excellent match has been observed between the present computed results and the available results in the literature which justifies applicability of the present DRP scheme to solve complex flow and aeroacoustic problems.

scholarly journals Gas-kinetic numerical study of complex flow problems covering various flow regimes

2011 ◽  
Vol 61 (12) ◽  
pp. 3653-3667 ◽  
Author(s):  
Zhi-Hui Li ◽  
Lin Bi ◽  
Han-Xin Zhang ◽  
Lin Li
Keyword(s):  
Numerical Study ◽  
Flow Regimes ◽  
Complex Flow ◽  
Flow Problems

An Approximate Model for the Static Operation of a Fluidic Amplifier Employing Axisymmetric Jets

1971 ◽  
Vol 93 (1) ◽  
pp. 47-54
Author(s):  
R. T. Johnson
Keyword(s):  
Mathematical Model ◽  
Approximate Model ◽  
Experimental Results ◽  
Complex Flow ◽  
Flow Problems ◽  
Axisymmetric Jets ◽  
Flow Phenomena ◽  
Static Operation ◽  
Approximate Mathematical Model ◽  
Downstream Flow

An approximate mathematical model for the static, no-load (blocked receiver) operation of a fluidic amplifier employing axisymmetric jets is developed. The amplifier is similar in concept to the three-terminal modulator developed by the Johnson Service Co. The approach used in developing the model assumes that the complex flow phenomena can be represented by the combination of several elementary flow problems. The model employs the concept of an equivalent power nozzle in describing downstream flow with a control signal present. Experimental results are presented to justify assumptions and evaluate parameters.

Sign in / Sign up

Export Citation Format

Share Document