scholarly journals A Wake Model for the Prediction of Propeller Performance at Low Advance Ratios

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Ye Tian ◽  
Spyros A. Kinnas
Keyword(s):  
Experimental Data ◽  
Panel Method ◽  
Model Based ◽  
Pressure Distributions ◽  
Alignment Model ◽  
Wake Model ◽  
Propeller Performance ◽  
Wake Alignment ◽  
Low Order

A low order panel method is used to predict the performance of propellers. A wake alignment model based on a pseudounsteady scheme is proposed and implemented. The results from this full wake alignment (FWA) model are correlated with available experimental data, and results from RANS for some propellers at design and low advance ratios. Significant improvements have been found in the predicted integrated forces and pressure distributions.

scholarly journals Prediction of Unsteady Developed Tip Vortex Cavitation and Its Effect on the Induced Hull Pressures

2020 ◽  
Vol 8 (2) ◽  
pp. 114 ◽  
Author(s):  
Seungnam Kim ◽  
Spyros A. Kinnas
Keyword(s):  
Panel Method ◽  
Ship Hull ◽  
Tip Vortex ◽  
Added Value ◽  
Navier Stokes ◽  
Solid Boundary ◽  
Maritime Industry ◽  
Unsteady Wake ◽  
Propeller Performance ◽  
Wake Alignment

Reducing the on-board noise and fluctuating pressures on the ship hull has been challenging and represent added value research tasks in the maritime industry. Among the possible sources for the unpalatable vibrations on the hull, propeller-induced pressures have been one of the main causes due to the inherent rotational motion of propeller and its proximity to the hull. In previous work, a boundary element method, which solves for the diffraction potentials on the ship hull due to the propeller, has been used to determine the propeller induced hull pressures. The flow around the propeller was evaluated via a panel method which solves in time for the propeller loading, trailing wake, and the sheet cavities. In this article, the propeller panel method is extended so that it also solves for the shape of developed tip vortex cavities, the effects of which are also included in the evaluation of the hull pressures. The employed unsteady wake alignment scheme is first applied, in the absence of cavitation, to investigate the propeller performance in non-axisymmetric inflow, such as the inclined-shaft flow or the flow behind an upstream body. In the latter case, the propeller panel method is coupled with a Reynolds-Averaged Navier–Stokes (RANS) solver to determine the effective wake at the propeller plane. The results, including the propeller induced hull pressures, are compared with those measured in the experiments as well as with those from RANS, where the propeller is also simulated as a solid boundary. Then the methods are applied in the cases where partial cavities and developed tip vortex cavities coexist. The predicted cavity patterns, the developed tip vortex trajectories, and the propeller-induced hull pressures are compared with those measured in the experiments.

A Panel Method with a Full Wake Alignment Model for the Prediction of the Performance of Ducted Propellers

2015 ◽  
Vol 59 (03) ◽  
pp. 246-257 ◽  
Author(s):  
Spyros A. Kinnas ◽  
Hongyang Fan ◽  
Ye Tian
Keyword(s):  
Panel Method ◽  
Navier Stokes ◽  
Ocean Engineering ◽  
Local Flow ◽  
University Of Texas ◽  
Alignment Model ◽  
Rans Simulations ◽  
Wake Alignment ◽  
Thrust And Torque ◽  
Ducted Propellers

An improved perturbation potential-based panel method is applied to model the flow around ducted propellers. One significant development in this method is the application of full wake alignment scheme in which the trailing vortex wake sheets of the blades are aligned with the local flow velocity by also considering the effects of duct and duct wake. A process of repaneling the duct is simultaneously introduced to improve the accuracy of the method. The results from the improved wake model are compared with those from a simplified wake alignment scheme. At the same time, full-blown Reynolds-averaged Navier-Stokes (RANS) simulations are conducted via commercial solvers. The forces, i.e., thrust and torque, on the propeller predicted by this panel method under the improved wake alignment model show good agreement both with experimental measurements, a hybrid method developed by the Ocean Engineering Group of University of Texas at Austin, and the full-blown RANS simulations. Moreover, predicted pressure distribution on the blades and duct are compared among the various methods.

scholarly journals Panel Method for Ducted Propellers with Sharp Trailing Edge Duct with Fully Aligned Wake on Blade and Duct

2018 ◽  
Vol 6 (3) ◽  
pp. 89 ◽  
Author(s):  
Seungnam Kim ◽  
Spyros Kinnas ◽  
Weikang Du
Keyword(s):  
Present Method ◽  
Panel Method ◽  
Trailing Edge ◽  
Ducted Propeller ◽  
Wide Range ◽  
Rans Simulations ◽  
Propeller Blades ◽  
Wake Alignment ◽  
Low Order ◽  
Ducted Propellers

A low-order panel method is used to predict the performance of ducted propellers. A full wake alignment (FWA) scheme, originally developed to determine the location of the force-free trailing wake of open propellers, is improved and extended to determine the location of the force-free trailing wakes of both the propeller blades and the duct, including the interaction with each other. The present method is applied on a ducted propeller with sharp trailing edge duct, and the predicted results over a wide range of advance ratios, with or without full alignment of the duct wake, are compared with each other, as well as with results from RANS simulations and with measurements from an experiment.

Fuzzy Modeling to Simulate Surface Roughness in CNC Turning of AISI 1045 Steel

2011 ◽  
Vol 486 ◽  
pp. 262-265
Author(s):  
Amit Kohli ◽  
Mudit Sood ◽  
Anhad Singh Chawla
Keyword(s):  
Experimental Data ◽  
Surface Roughness ◽  
Process Parameters ◽  
Fuzzy Model ◽  
Fuzzy Modeling ◽  
Cnc Machine ◽  
Model Based ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
1045 Steel

The objective of the present work is to simulate surface roughness in Computer Numerical Controlled (CNC) machine by Fuzzy Modeling of AISI 1045 Steel. To develop the fuzzy model; cutting depth, feed rate and speed are taken as input process parameters. The predicted results are compared with reliable set of experimental data for the validation of fuzzy model. Based upon reliable set of experimental data by Response Surface Methodology twenty fuzzy controlled rules using triangular membership function are constructed. By intelligent model based design and control of CNC process parameters, we can enhance the product quality, decrease the product cost and maintain the competitive position of steel.

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