CFD analysis of unsteady propeller performance operating at different inclined shaft angles for long-tail boat in Thailand

2020 ◽  
Vol 17 (2) ◽  
pp. 115-127
Author(s):  
Prachakon Kaewkhiaw
Keyword(s):  
High Speed ◽  
Cross Flow ◽  
Navier Stokes ◽  
Flow Conditions ◽  
Wake Effect ◽  
Long Tail ◽  
Shaft Angle ◽  
Propeller Blades ◽  
Time Accuracy ◽  
Propeller Performance

Inclined shaft propeller arrangements are demonstrated in the high-speed boat. The flow field around the propeller blades with inclined shaft propeller is unsteady due to the cross-flow component from the influx of the shaft direction which complicated more than the straight shaft propeller condition (without inclined shaft propeller). Therefore, realistic flow around inclined shaft propeller is important to the actual efficiency of propeller. In addition, propeller characteristics such as the pitch, skew and rake are influences to propeller performance, maybe not done in design condition which is different from the straight shaft propeller. This paper offers the investigation of unsteady propeller performance with operating the different inclined shaft angle conditions for Long-Tail Boat (LTB) using a Reynolds Averaged Navier-Stokes (RANS) solver. The unsteady calculations are conducted by inclined flow conditions. The computational results of propeller performance and pressure distribution on the suction and pressure sides at the blades of time-accuracy have been compared to each other including the wake effect behind the propeller. The results can be applied to adjust the inclined shaft angle of the boat.

scholarly journals CFD investigation on steady and unsteady performances of contra-rotating propellers

2018 ◽  
Vol 15 (2) ◽  
pp. 91-105 ◽  
Author(s):  
Prachakon Kaewkhiaw
Keyword(s):  
Velocity Vector ◽  
Measurement Data ◽  
Transverse Plane ◽  
Navier Stokes ◽  
Interaction Forces ◽  
Calculation Results ◽  
Propeller Blades ◽  
Time Accuracy ◽  
Propeller Performance ◽  
Vector Magnitude

The realistic flow on each blade of the front and rear propellers with contra-rotating propellers (CRPs) are most complex because that consist the interaction forces with themselves and it affects to the actual efficiency of the propeller blades. The wake of CRPs at the gap between the front and rear propellers have influent to the variation of propeller performance for the front and rear propellers. So, this paper presented the numerical simulation of propeller performance on CRPs with steady method in the first. Second, it is applied to evaluate the propeller performance with unsteady method in time accuracy including investigating the wake on a transverse plane between the front and rear propellers and a transverse plane located downstream of the rear propeller. The wake was analyzed through velocity vector magnitude contours. The numerical simulations were conducted using the Reynolds Averaged Navier-Stokes (RANS). The calculation results have been compared the measurement data.

scholarly journals Simulations of a Single-Phase Flow in a Compound Parabolic Concentrator Reactor

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Tzayam Pérez ◽  
José L. Nava
Keyword(s):  
Turbulent Flow ◽  
Flow Visualization ◽  
High Speed ◽  
Turbulent Viscosity ◽  
Navier Stokes ◽  
Flow Conditions ◽  
Compound Parabolic Concentrator ◽  
Convection Model ◽  
Diffusion Convection ◽  
Turbulent Flow Conditions

This paper deals with the analysis and interpretation of flow visualization and residence time distribution (RTD) in a compound parabolic concentrator (CPC) reactor using computational fluid dynamics (CFD). CFD was calculated under turbulent flow conditions solving the Reynolds averaged Navier–Stokes (RANS) equation expressed in terms of turbulent viscosity and the standard k−ε turbulent model in 3D. A 3D diffusion-convection model was implemented in the CPC reactor to determine the RTD. The fluid flow visualization and RTD were validated with experimental results. The CFD showed that the magnitude of the velocity field remains almost uniform in most of the bulk reactor, although near and inside the 90° connectors and the union segments, the velocity presented low- and high-speed zones. Comparisons of theoretical and experimental RTD curves showed that the k−ε model is appropriate to simulate the nonideal flow inside the CPC reactor under turbulent flow conditions.

Study of Turbulent Models in Jet Impingement at Different Cross-Flow Conditions

2017 ◽  
Vol 17 (17th International Conference) ◽  
pp. 1-21
Author(s):  
Abd Elnaby Kabeel ◽  
Medhat Elkelawy ◽  
Hagar Bastawissi ◽  
Ahmed El-Banna
Keyword(s):  
Cross Flow ◽  
Jet Impingement ◽  
Flow Conditions ◽  
Turbulent Models

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.

scholarly journals Cross-Flow Tidal Turbines with Highly Flexible Blades—Experimental Flow Field Investigations at Strong Fluid–Structure Interactions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 797
Author(s):  
Stefan Hoerner ◽  
Iring Kösters ◽  
Laure Vignal ◽  
Olivier Cleynen ◽  
Shokoofeh Abbaszadeh ◽  
...  
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Cross Flow ◽  
Speed Ratio ◽  
Fluid Structure Interactions ◽  
Dimensional Parameter ◽  
Fluid Structure ◽  
Passive Flow Control ◽  
Tidal Turbines ◽  
Tidal Turbine

Oscillating hydrofoils were installed in a water tunnel as a surrogate model for a hydrokinetic cross-flow tidal turbine, enabling the study of the effect of flexible blades on the performance of those devices with high ecological potential. The study focuses on a single tip-speed ratio (equal to 2), the key non-dimensional parameter describing the operating point, and solidity (equal to 1.5), quantifying the robustness of the turbine shape. Both parameters are standard values for cross-flow tidal turbines. Those lead to highly dynamic characteristics in the flow field dominated by dynamic stall. The flow field is investigated at the blade level using high-speed particle image velocimetry measurements. Strong fluid–structure interactions lead to significant structural deformations and highly modified flow fields. The flexibility of the blades is shown to significantly reduce the duration of the periodic stall regime; this observation is achieved through systematic comparison of the flow field, with a quantitative evaluation of the degree of chaotic changes in the wake. In this manner, the study provides insights into the mechanisms of the passive flow control achieved through blade flexibility in cross-flow turbines.

Stationary cross-flow breakdown in a high-speed swept-wing boundary layer

2021 ◽  
Vol 33 (2) ◽  
pp. 024108
Author(s):  
Jianqiang Chen ◽  
Siwei Dong ◽  
Xi Chen ◽  
Xianxu Yuan ◽  
Guoliang Xu
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Cross Flow ◽  
Swept Wing

Exact Navier-Stokes Solutions Including Swirl and Cross Flow

1967 ◽  
Vol 10 (7) ◽  
pp. 1438 ◽  
Author(s):  
Sheldon Weinbaum
Keyword(s):  
Cross Flow ◽  
Navier Stokes

Reynolds-averaged Navier–Stokes simulation of hydrofoil effects on hydrodynamic coefficients of a catamaran in forced oscillation

2016 ◽  
Vol 231 (2) ◽  
pp. 364-383
Author(s):  
Amin Najafi ◽  
Mohammad Saeed Seif
Keyword(s):  
High Speed ◽  
Experimental Approach ◽  
Navier Stokes ◽  
Hydrodynamic Coefficients ◽  
Laboratory Equipment ◽  
Factors Affecting ◽  
High Frequencies ◽  
Frequency Independent ◽  
Reynolds Averaged Navier Stokes

Determination of high-speed crafts’ hydrodynamic coefficients will help to analyze the dynamics of these kinds of vessels and the factors affecting their dynamic stabilities. Also, it can be useful and effective in controlling the vessel instabilities. The main purpose of this study is to determine the coefficients of longitudinal motions of a planing catamaran with and without a hydrofoil using Reynolds-averaged Navier–Stokes method to evaluate the foil effects on them. Determination of hydrodynamic coefficients by experimental approach is costly and requires meticulous laboratory equipment; therefore, utilizing the numerical methods and developing a virtual laboratory seem highly efficient. In this study, the numerical results for hydrodynamic coefficients of a high-speed craft are verified against Troesch’s experimental results. In the following, after determination of hydrodynamic coefficients of a planing catamaran with and without foil, the foil effects on its hydrodynamic coefficients are evaluated. The results indicate that most of the coefficients are frequency-independent especially at high frequencies.

scholarly journals High-speed propeller performance and noise predictions at takeoff/landing conditions

1989 ◽  
Vol 26 (6) ◽  
pp. 563-569 ◽  
Author(s):  
M. Nallasamy ◽  
R. P. Woodward ◽  
J. F. Groeneweg
Keyword(s):  
High Speed ◽  
Propeller Performance
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