scholarly journals Numerical Analysis of Aerofoil Shape Propeller Boss Cap Fin (PBCF) to Improve Propeller Efficiency

2020 ◽  
Vol 9 (3) ◽  
pp. 231-238
Keyword(s):  
Fossil Fuel ◽  
Fluid Dynamic ◽  
Environmental Issues ◽  
Navier Stokes ◽  
Pressure Side ◽  
Flow Phenomenon ◽  
Thrust Generation ◽  
Propeller Performance ◽  
High Thrust ◽  
Marine Vehicle

Scarcity in fossil fuel and other environmental issues forced researchers to search ways to improve in the efficiency of the marine vehicle which is considered the most efficient and economic transport medium now a day. Energy saving device (ESD) is such an implementation to keep dominant impact in this aspect. This paper investigates the effect of aerofoil shape propeller boss cap fin (PBCF) as ESD computationally. Based on Reynolds- averaged Navier-Stokes (RANS) equations, numerical simulations have been performed to increase propeller efficiency with aerofoil shape propeller boss cap fin in computational fluid dynamic (CFD) approach. In this study, four separate aerofoil shape PBCF with different NACA profile (NACA4412, NACA0012, NACA1412, NACA2412) has been used to find a suitable profile for PBCF. Numerical results shows aerofoil shape PBCF with NACA4412 effectively improves propeller performance by improving the efficiency by approximately 3.52% than parent propeller. The pressure distribution elaborate PBCF (NACA4412) creates a high pressure difference between the pressure side and suction of the propeller as well as high thrust generation. Besides that velocity filed, swirl strength are also studied to get and understand the details of involved flow phenomenon.

Recent Developments in Computational Methods for the Analysis of Ducted Propellers in Open Water

2019 ◽  
Vol 63 (4) ◽  
pp. 219-234
Author(s):  
João Baltazar ◽  
José A. C. Falcão de Campos ◽  
Johan Bosschers ◽  
Douwe Rijpkema
Keyword(s):  
Computational Methods ◽  
Open Water ◽  
Boundary Element Methods ◽  
Navier Stokes ◽  
Hydrodynamic Analysis ◽  
Numerical Predictions ◽  
Ducted Propeller ◽  
Recent Developments ◽  
Propeller Performance ◽  
Ducted Propellers

This article presents an overview of the recent developments at Instituto Superior Técnico and Maritime Research Institute Netherlands in applying computational methods for the hydrodynamic analysis of ducted propellers. The developments focus on the propeller performance prediction in open water conditions using boundary element methods and Reynolds-averaged Navier-Stokes solvers. The article starts with an estimation of the numerical errors involved in both methods. Then, the different viscous mechanisms involved in the ducted propeller flow are discussed and numerical procedures for the potential flow solution proposed. Finally, the numerical predictions are compared with experimental measurements.

The inlet flow structure of a conceptual open-nose supersonic drone

2021 ◽  
pp. 095441002098304
Author(s):  
Eiman B Saheby ◽  
Xing Shen ◽  
Anthony P Hays ◽  
Zhang Jun
Keyword(s):  
Flow Structure ◽  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Computational Fluid Dynamic Simulation ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Aerodynamic Efficiency ◽  
Performance Effects

This study describes the aerodynamic efficiency of a forebody–inlet configuration and computational investigation of a drone system, capable of sustainable supersonic cruising at Mach 1.60. Because the whole drone configuration is formed around the induction system and the design is highly interrelated to the flow structure of forebody and inlet efficiency, analysis of this section and understanding its flow pattern is necessary before any progress in design phases. The compression surface is designed analytically using oblique shock patterns, which results in a low drag forebody. To study the concept, two inlet–forebody geometries are considered for Computational Fluid Dynamic simulation using ANSYS Fluent code. The supersonic and subsonic performance, effects of angle of attack, sideslip, and duct geometries on the propulsive efficiency of the concept are studied by solving the three-dimensional Navier–Stokes equations in structured cell domains. Comparing the results with the available data from other sources indicates that the aerodynamic efficiency of the concept is acceptable at supersonic and transonic regimes.

Computational Fluid Dynamic Using Parallel Loop of Multi-Cores Processor

2014 ◽  
Vol 493 ◽  
pp. 80-85 ◽  
Author(s):  
C.L Siow ◽  
Jaswar ◽  
Efi Afrizal
Keyword(s):  
Fluid Flow ◽  
Early Stage ◽  
Fluid Dynamic ◽  
Visual Basic ◽  
Computer Hardware ◽  
Navier Stokes ◽  
Computer Memory ◽  
Large Size ◽  
Computational Fluid Dynamics Cfd ◽  
Reynolds Average

Computational Fluid Dynamics (CFD) software is often used to study fluid flow and structures motion in fluids. The CFD normally requires large size of arrays and computer memory and then caused long execution time. However, Innovation of computer hardware such as multi-cores processor provides an alternative solution to improve this programming performance. This paper discussed loop parallelize multi-cores processor for optimization of sequential looping CFD code. This loop parallelize CFD was achieved by applying multi-tasking or multi-threading code into the original CFD code which was developed by one of the authors. The CFD code was developed based on Reynolds Average Navier-Stokes (RANS) method. The new CFD code program was developed using Microsoft Visual Basic (VB) programming language. In the early stage, the whole CFD code was constructed in a sequential flow before it is modified to parallel flow by using VBs multi-threading library. In the comparison, fluid flow around the hull of round-shaped FPSO was selected to compare the performance of both the programming codes. Besides, executed results of this self-developed code such as pressure distribution around the hull were also presented in this paper.

scholarly journals Hydrodynamic limits of kinetic equations for polyatomic and reactive gases

2017 ◽  
Vol 8 (1) ◽  
pp. 23-42 ◽  
Author(s):  
M. Bisi ◽  
G. Spiga
Keyword(s):  
Degrees Of Freedom ◽  
Continuum Limit ◽  
Fluid Dynamic ◽  
Energy Levels ◽  
Kinetic Equations ◽  
Navier Stokes ◽  
Bgk Model ◽  
Hydrodynamic Limits ◽  
Stress Diffusion ◽  
Reactive Gases

Abstract Starting from a kinetic BGK-model for a rarefied polyatomic gas, based on a molecular structure of discrete internal energy levels, an asymptotic Chapman-Enskog procedure is developed in the asymptotic continuum limit in order to derive consistent fluid-dynamic equations for macroscopic fields at Navier-Stokes level. In this way, the model allows to treat the gas as a mixture of mono-atomic species. Explicit expressions are given not only for dynamical pressure, but also for shear stress, diffusion velocities, and heat flux. The analysis is shown to deal properly also with a mixture of reactive gases, endowed for simplicity with translational degrees of freedom only, in which frame analogous results can be achieved.

Computational Fluid Dynamic Applications for Jet Propulsion System Integration

1991 ◽  
Vol 113 (1) ◽  
pp. 40-50 ◽  
Author(s):  
R. H. Tindell
Keyword(s):  
System Integration ◽  
Fluid Dynamic ◽  
Low Cost ◽  
Separated Flow ◽  
Propulsion System ◽  
Navier Stokes ◽  
Aerospace Vehicles ◽  
Design Engineers ◽  
Flow Phenomena ◽  
The Impact

The impact of computational fluid dynamics (CFD) methods on the development of advanced aerospace vehicles is growing stronger year by year. Design engineers are now becoming familiar with CFD tools and are developing productive methods and techniques for their applications. This paper presents and discusses applications of CFD methods used at Grumman to design and predict the performance of propulsion system elements such as inlets and nozzles. The paper demonstrates techniques for applying various CFD codes and shows several interesting and unique results. A novel application of a supersonic Euler analysis of an inlet approach flow field, to clarify a wind tunnel-to-flight data conflict, is presented. In another example, calculations and measurements of low-speed inlet performance at angle of attack are compared. This is highlighted by employing a simplistic and low-cost computational model. More complex inlet flow phenomena at high angles of attack, calculated using an approach that combines a panel method with a Navier-Stokes (N-S) code, is also reviewed. The inlet fluid mechanics picture is rounded out by describing an N-S calculation and a comparison with test data of an offset diffuser having massively separated flow on one wall. Finally, the propulsion integration picture is completed by a discussion of the results of nozzle-afterbody calculations, using both a complete aircraft simulation in a N-S code, and a more economical calculation using an equivalent body of revolution technique.

Process of metal−organic framework (MOF)/covalent−organic framework (COF) hybrids-based derivatives and their applications on energy transfer and storage

Nanoscale ◽  
2022 ◽  
Author(s):  
Bingbing Cui ◽  
Guo-Dong Fu
Keyword(s):  
Renewable Energy ◽  
Energy Transfer ◽  
Fossil Fuel ◽  
Metal Organic Framework ◽  
Renewable Energy Sources ◽  
Environmental Issues ◽  
Energy Sources ◽  
Metal Organic ◽  
And Storage ◽  
Organic Framework

The fossil-fuel shortage and severe environmental issues have posed ever-increasing demands on clean and renewable energy sources, for which the exploration of electrocatalysts has been in a big challenge toward...

Simulation of Vortex Instability in a Pipe Trifurcation

2003 ◽  
Author(s):  
Albert Ruprecht ◽  
Ralf Neubauer ◽  
Thomas Helmrich
Keyword(s):  
Large Eddy Simulation ◽  
Turbulence Model ◽  
Model Test ◽  
Reasonable Agreement ◽  
Navier Stokes ◽  
Extended Version ◽  
Vortex Instability ◽  
Flow Phenomenon ◽  
Eddy Simulation ◽  
Large Eddy

The vortex instability in a spherical pipe trifurcation is investigated by applying a Very Large Eddy Simulation (VLES). For this approach an new adaptive turbulence model based on an extended version of the k-ε model is used. Applying a classical Reynolds-averaged Navier-Stokes-Simulation with the standard k-ε model is not able to forecast the vortex instability. However the prescribed VLES method is capable to predict this flow phenomenon. The obtained results show a reasonable agreement with measurements in a model test.

Experimental and Numerical Study of Vortex Induced Vibrations on a Spool Model

2018 ◽  
Author(s):  
David Gross ◽  
Yann Roux ◽  
Benjamin Rousse ◽  
François Pétrié ◽  
Ludovic Assier ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Perturbation ◽  
Industry Standards ◽  
Vortex Induced Vibrations ◽  
Recommended Practices ◽  
Decay Tests

The problem of Vortex-Induced Vibrations (VIV) on spool and jumper geometries is known to present several drawbacks when approached with conventional engineering tools used in the study of VIV on risers. Current recommended practices can lead to over-conservatism that the industry needs to quantify and minimize within notably cost reduction objectives. Within this purpose, the paper will present a brief critical review of the Industry standards and more particularly focus on both experimental and Computational Fluid Dynamic (CFD) approaches. Both qualitative and quantitative comparisons between basin tests and CFD results for a 2D ‘M-shape’ spool model will be detailed. The results presented here are part of a larger experimental and numerical campaign which considered a number of current velocities, heading and geometry configurations. The vibratory response of the model will be investigated for one of the current velocities and compared with the results obtained through recommended practices (e.g. Shear7 and DNV guidelines). The strategy used by the software K-FSI to solve the fluid-structure interaction (FSI) problem is a partitioned coupling solver between fluid solver (FINE™/Marine) and structural solvers (ARA). FINE™/Marine solves the Reynolds-Averaged Navier-Stokes Equations in a conservative way via the finite volume method and can work on structured or unstructured meshes with arbitrary polyhedrons, while ARA is a nonlinear finite element solver with a large displacement formulation. The experiments were conducted in the BGO FIRST facility located in La Seyne sur Mer, France. Particular attention was paid towards the model design, fabrication, instrumentation and characterization, to ensure an excellent agreement between the structural numerical model and the actual physical model. This included the use of a material with low structural damping, the performance of stiffness and decay tests in air and in still water, plus the rationalization of the instrumentation to be able to capture the response with the minimum flow perturbation or interaction due to instrumentation.

Modular Turbulence Modeling Applied to an Engine Intake

2013 ◽  
Vol 136 (5) ◽  
Author(s):  
Ugochukwu R. Oriji ◽  
Paul G. Tucker
Keyword(s):  
Surface Roughness ◽  
Turbulence Modeling ◽  
Fluid Dynamic ◽  
Navier Stokes ◽  
Test Cases ◽  
Laminar Separation ◽  
Streamline Curvature ◽  
Favorable Pressure Gradient ◽  
Flow Features ◽  
The One

The one equation Spalart–Allmaras (SA) turbulence model in an extended modular form is presented. It is employed for the prediction of crosswind flow around the lip of a 90 deg sector of an intake with and without surface roughness. The flow features around the lip are complex. There exists a region of high streamline curvature. For this, the Richardson number would suggest complete degeneration to laminar flow. Also, there are regions of high favorable pressure gradient (FPG) sufficient to laminarize a turbulent boundary layer (BL). This is all terminated by a shock and followed by a laminar separation. Under these severe conditions, the SA model is insensitive to capturing the effects of laminarization and the reenergization of eddy viscosity. The latter promotes the momentum transfer and correct reattachment prior to the fan face. Through distinct modules, the SA model has been modified to account for the effect of laminarization and separation induced transition. The modules have been implemented in the Rolls-Royce HYDRA computational fluid dynamic (CFD) solver. They have been validated over a number of experimental test cases involving laminarization and also surface roughness. The validated modules are finally applied in unsteady Reynolds-averaged Navier–Stokes (URANS) mode to flow around an engine intake and comparisons made with measurements. Encouraging agreement is found and hence advances made towards a more reliable intake design framework.

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