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H. Reksoprodjo - One of the best experts on this subject based on the ideXlab platform.

  • Cavitating Propeller Flows Predicted by RANS Solver with Structured Grid and Small Reynolds Number Turbulence Model Approach
    2016
    Co-Authors: Tuomas Sipilä, I. Saisto, Jussi Martio, Timo Siikonen, H. Reksoprodjo
    Abstract:

    Within the EU research project VIRTUE, a Propeller is investigated in uniform and non-uniform inflow conditions by means of a RANS equation solver, FINFLO. The analyses are made in wetted and Cavitating conditions. The Propeller analyzed in this paper is the INSEAN E779A Propeller. The paper contains calculations at three different grid resolutions in wetted conditions and at the two finest grid resolutions in Cavitating conditions in uniform inflow. The medium-size grid is used for the Propeller in non-uniform inflow simulations. The simulations are conducted on a model scale and the results are compared with the measurements and cavitation tests performed by INSEAN. The non-uniform inflow is generated by modeling the geometry of the artificial wake generator used in the cavitatio

  • Cavitating Propeller flows predicted by RANS solver with structured grid and small reynolds number turbulence model approach
    2009
    Co-Authors: Tuomas Sipilä, I. Saisto, Jussi Martio, Timo Siikonen, H. Reksoprodjo
    Abstract:

    Within the EU research project VIRTUE, a Propeller is investigated in uniform and non-uniform inflow conditions by means of a RANS equation solver, FINFLO. The analyses are made in wetted and Cavitating conditions. The Propeller analyzed in this paper is the INSEAN E779A Propeller. The paper contains calculations at three different grid resolutions in wetted conditions and at the two finest grid resolutions in Cavitating conditions in uniform inflow. The medium-size grid is used for the Propeller in nonuniform inflow simulations. The simulations are conducted on a model scale and the results are compared with the measurements and cavitation tests performed by INSEAN. The non-uniform inflow is generated by modeling the geometry of the artificial wake generator used in the cavitation tests in the calculation domain. The experimental results are published in several papers, for example in [1] and [2]. The predicted Propeller open water thrust and torque are found to be within 5 % of the measured ones. The pressure peak at the leading edge of a blade is found to be sensitive to the grid resolution. The predicted cavitation behavior of the Propeller blades is in reasonable accordance with the cavitation test observations. In uniform inflow the vaporized region is over-predicted. Contrastingly, the vaporized region is under-predicted in the non-uniform inflow calculations. Side entrant jets could be identified in the cavity region in the nonuniform inflow simulations. The predicted vaporized regions in several blade positions together with photographs of the Cavitating Propeller are shown for comparison. The cavitation behavior trends seemed to be similar in the simulations and observations in non-uniform inflow, except that the roll-up of detached sheet cavitation into a tip vortex could not be captured in the calculations. The total wake is measured between the Propeller plane and the wake generator. The predicted wake is found to be too strong, but the width of the wake is relatively close to the measurements. The Propeller loading history is shown over one Propeller revolution. It shows qualitatively reasonable trends. The loading histories of the wetted and Cavitating Propeller are almost the same due to the relative small Cavitating region in the investigated conditions. The pressure distributions at several blade positions on the suction side of the Propeller are shown in wetted and Cavitating conditions for comparison. INTRODUCTION Cavitation produces a number of problems in Propeller flows. The Cavitating tip vortex collapse as well as the fluctuating type of sheet cavitation can cause noise in the interior of the ship and in the environment. The cavitation can also cause erosive behavior on Propeller blades and on devices in the slipstream of the Propeller, for example on rudders. In practice, a ship’s Propeller operates in an inhomogeneous wake field, where the velocity and direction of the flow in relation to the Propeller blades vary during the rotation. For practical Propeller analysis it is important to model both the cavitation phenomena and the unsteadiness of the inflow. In the mid-1990s VTT Technical Research Centre of Finland started using FINFLO for Propeller flow analyses [3]. In the present study FINFLO is used to simulate nonCavitating and Cavitating Propeller flows. The RANS equation solver – called FINFLO – is developed by Helsinki University of Technology (TKK) [4]. During recent projects, TKK has extended the FINFLO code to the simulation of multi-phase flows. At this stage the Merkle’s mass transfer model for Cavitating flows [5] is implemented for the phase transition. The Propeller analyzed in this paper is a modified Wageningen type Propeller, the INSEAN E779A, which has an extensive experimental database [1], [2]. Because the test results of the Propeller are very thoroughly documented, it was

Ge Muye - One of the best experts on this subject based on the ideXlab platform.

  • Numerical prediction of Propeller induced hull pressure pulses and noise
    2021
    Co-Authors: Ge Muye
    Abstract:

    An operating marine Propeller is one of the major sources inducing hull pressure pulses, onboard noise and vibration as well as underwater radiated noise. There are rising concerns of environmental impacts and comfort and welfare of passengers and crews due to these negative effects. Cavitation is a significant source of these effects, but it is typically inevitable if only the hydrodynamic efficiency of the Propeller is optimized. To reduce the noise and the pressure pulses caused by the cavitation, a trade-off of the hydrodynamic efficiency should be made to design and optimize a Propeller that possess both high hydrodynamic performance and low noise and hull pressure pulse generation. More accurate predictions are needed to identify the best trade-off between a high efficiency Propeller design and a low pressure pulse and noise one.The study focuses on the numerical prediction of hull pressure pulses and radiated underwater noise using viscous CFD including the opensource package OpenFOAM and commercial package Star-CCM+. Numerical predictions are performed regarding different experimental configurations for determining hull pressure pulses and ship noise, including Propellers mounted on inclined shafts and Propellers operating behind ship hulls, under different scales and scaling laws with different operating conditions and Reynolds numbers.Non-Cavitating Propeller induced pressure pulses are generally lower in levels and rich in blade passing frequency comparing to Cavitating conditions, with blade tip clearance as a major impact factor. For Cavitating conditions the rate of cavity growth/shrinkage is found to play the dominating role generating pressure fluctuations. For certain model scale configurations, numerical predictions with ordinary approaches predict massive sheet cavity on Propeller blades leading to pressure pulse prediction discrepancies comparing to experimental observations and measurements. These can be significantly improved by a developed bridged model considering laminar to turbulence transition. Tip vortex cavitation bursting is a common phenomenon found on Propellers operating behind the ship hull and generating significant levels of pressure pulses. The phenomenon is numerically predicted with investigations of its generation mechanisms in relation to the Propeller inflow, convex shaped sheet cavitation closure line and traveling re-entrant jet underneath the sheet cavity.Propeller induced noise prediction was studied using approaches focused on the FWH (Ffowcs Williams-Hawkings) acoustic analogy with incompressible input on permeable/porous data surface (PDS). \ua0Studies show this combination between incompressible input and FWH acoustic analogy can be erroneous, though using certain PDS placements and closer receivers the error can be reduced

  • Investigation on Numerical Prediction of Propeller Induced Hull Pressure Pulses
    2018
    Co-Authors: Ge Muye, Bensow Rickard, Svennberg Urban
    Abstract:

    Simulation of a Cavitating Propeller in behind conditions and analysis of induced hull pressure fluctuations are presented. All the simulations were performed using RANS method in the commercial package Star-CCM+. Cavitation patterns show good agreement with experimental measurements, especially the blade tip refined meshes which captured the dynamic behaviour of tip vortex cavitation. The predicted pressure pulse amplitudes agree reasonably well with experimental measurements up to 3rd to 4th order of blade passing frequency

Tuomas Sipilä - One of the best experts on this subject based on the ideXlab platform.

  • Cavitating Propeller Flows Predicted by RANS Solver with Structured Grid and Small Reynolds Number Turbulence Model Approach
    2016
    Co-Authors: Tuomas Sipilä, I. Saisto, Jussi Martio, Timo Siikonen, H. Reksoprodjo
    Abstract:

    Within the EU research project VIRTUE, a Propeller is investigated in uniform and non-uniform inflow conditions by means of a RANS equation solver, FINFLO. The analyses are made in wetted and Cavitating conditions. The Propeller analyzed in this paper is the INSEAN E779A Propeller. The paper contains calculations at three different grid resolutions in wetted conditions and at the two finest grid resolutions in Cavitating conditions in uniform inflow. The medium-size grid is used for the Propeller in non-uniform inflow simulations. The simulations are conducted on a model scale and the results are compared with the measurements and cavitation tests performed by INSEAN. The non-uniform inflow is generated by modeling the geometry of the artificial wake generator used in the cavitatio

  • Cavitating Propeller flows predicted by RANS solver with structured grid and small reynolds number turbulence model approach
    2009
    Co-Authors: Tuomas Sipilä, I. Saisto, Jussi Martio, Timo Siikonen, H. Reksoprodjo
    Abstract:

    Within the EU research project VIRTUE, a Propeller is investigated in uniform and non-uniform inflow conditions by means of a RANS equation solver, FINFLO. The analyses are made in wetted and Cavitating conditions. The Propeller analyzed in this paper is the INSEAN E779A Propeller. The paper contains calculations at three different grid resolutions in wetted conditions and at the two finest grid resolutions in Cavitating conditions in uniform inflow. The medium-size grid is used for the Propeller in nonuniform inflow simulations. The simulations are conducted on a model scale and the results are compared with the measurements and cavitation tests performed by INSEAN. The non-uniform inflow is generated by modeling the geometry of the artificial wake generator used in the cavitation tests in the calculation domain. The experimental results are published in several papers, for example in [1] and [2]. The predicted Propeller open water thrust and torque are found to be within 5 % of the measured ones. The pressure peak at the leading edge of a blade is found to be sensitive to the grid resolution. The predicted cavitation behavior of the Propeller blades is in reasonable accordance with the cavitation test observations. In uniform inflow the vaporized region is over-predicted. Contrastingly, the vaporized region is under-predicted in the non-uniform inflow calculations. Side entrant jets could be identified in the cavity region in the nonuniform inflow simulations. The predicted vaporized regions in several blade positions together with photographs of the Cavitating Propeller are shown for comparison. The cavitation behavior trends seemed to be similar in the simulations and observations in non-uniform inflow, except that the roll-up of detached sheet cavitation into a tip vortex could not be captured in the calculations. The total wake is measured between the Propeller plane and the wake generator. The predicted wake is found to be too strong, but the width of the wake is relatively close to the measurements. The Propeller loading history is shown over one Propeller revolution. It shows qualitatively reasonable trends. The loading histories of the wetted and Cavitating Propeller are almost the same due to the relative small Cavitating region in the investigated conditions. The pressure distributions at several blade positions on the suction side of the Propeller are shown in wetted and Cavitating conditions for comparison. INTRODUCTION Cavitation produces a number of problems in Propeller flows. The Cavitating tip vortex collapse as well as the fluctuating type of sheet cavitation can cause noise in the interior of the ship and in the environment. The cavitation can also cause erosive behavior on Propeller blades and on devices in the slipstream of the Propeller, for example on rudders. In practice, a ship’s Propeller operates in an inhomogeneous wake field, where the velocity and direction of the flow in relation to the Propeller blades vary during the rotation. For practical Propeller analysis it is important to model both the cavitation phenomena and the unsteadiness of the inflow. In the mid-1990s VTT Technical Research Centre of Finland started using FINFLO for Propeller flow analyses [3]. In the present study FINFLO is used to simulate nonCavitating and Cavitating Propeller flows. The RANS equation solver – called FINFLO – is developed by Helsinki University of Technology (TKK) [4]. During recent projects, TKK has extended the FINFLO code to the simulation of multi-phase flows. At this stage the Merkle’s mass transfer model for Cavitating flows [5] is implemented for the phase transition. The Propeller analyzed in this paper is a modified Wageningen type Propeller, the INSEAN E779A, which has an extensive experimental database [1], [2]. Because the test results of the Propeller are very thoroughly documented, it was

Atlar Mehmet - One of the best experts on this subject based on the ideXlab platform.

  • Prediction of Cavitating Propeller underwater radiated noise using RANS & DES-based hybrid method
    'Informa UK Limited', 2021
    Co-Authors: Sezen Savas, Atlar Mehmet, Fitzsimmons Patrick
    Abstract:

    This study focuses on the prediction of the hydrodynamic and hydroacoustic performance of a Cavitating marine Propeller in open water condition using Reynolds-averaged Navier-Stokes (RANS) and Detached Eddy Simulation (DES) solvers. The effectiveness of the methods is investigated for the recently introduced benchmark Propeller that belongs to the research vessel "The Princess Royal". The main emphasis of the study is to examine the capabilities of the RANS and DES solvers for predicting the hydrodynamic performance of a Propeller in the presence of sheet and tip vortex cavitation (TVC). In the numerical simulations of the Cavitating Propeller flow, the Schnerr-Sauer cavitation model based on a reduced Rayleigh-Plesset equation was used to model the sheet and tip vortex cavitation. An alternative vorticity-based adaptive mesh refinement (VAMR) technique was employed for the accurate realisation of the TVC in the Propeller's slipstream. In the hydroacoustic calculations, a porous Ffowcs Williams Hawkings equation (P-FWH) was employed together with the DES solver. The numerical hydrodynamic and hydroacoustic results are compared with those of experimental data for the benchmark Propeller available from the University of Genova Cavitation Tunnel. The results show that both the RANS and DES solvers are successful for modelling of the sheet cavitation on the Propeller blades. However, the prediction of the TVC extension using the RANS solver is found to be insufficient in comparison to the TVC prediction when using the DES method. This is due to the inherent modelling limitations of the RANS solver. In addition to hydrodynamic performance predictions, the overall noise spectrums were found in an agreement with the experimental data with discrepancies between the low and high-frequency region

  • Numerical investigation of full-scale Cavitating Propeller underwater radiated noise
    2021
    Co-Authors: Sezen Savas, Atlar Mehmet, Aktas Batuhan, Fitzsimmons Patrick
    Abstract:

    This study aims to predict the full-scale Propeller Underwater Radiated Noise (URN) in Cavitating and non-uniform flow conditions using a viscous flow-based hybrid method. The recently introduced benchmark Propeller of the research vessel, "The Princess Royal", was used for the numerical application to validate the methodology presented in this paper. The hybrid method constitutes a DES (Detached Eddy Simulation) solver coupled with a porous formulation of the Ffowcs Williams Hawking Equations (P-FWH) for the URN predictions. The Schnerr-Sauer cavitation model based on the reduced Rayleigh-Plesset equation was utilised to model the sheet and tip vortex cavitation (TVC). A vorticity-based Adaptive Mesh Refinement (V-AMR) technique was proposed and implemented for better modelling of the TVC in the Propeller's slipstream. The hydrodynamic performance, including the cavity patterns and URN results, were compared with the full-scale URN data collected from the sea trials with The Princess Royal. The predicted Propeller URN results show good agreement with the trials data except for some discrepancies in the high-frequency region of the noise spectra investigated

  • On-board measurement techniques to quantify underwater radiated noise level
    'Elsevier BV', 2017
    Co-Authors: Turkmen Serkan, Atlar Mehmet, Aktas Batuhan, Sasaki Noriyuki, Sampson Rod, Shi Weichao
    Abstract:

    Cavitating ship Propellers are known to be the dominant noise source contributing significantly to the underwater radiated noise (URN) level. Innovative measurement methods using on-board devices need to be further investigated as they offer a serious alternative to traditional methods in terms of cost-efficiency and practicality. This exploratory study combined simultaneous on- and off-board noise and vibration measurements with cavitation views captured by digital photography and high speed cameras.Comprehensive full-scale trials were conducted on Newcastle University’s research vessel, The Princess Royal, in the framework of the FP7-EU project SONIC. On-board data were captured from multiple measurement systems (including. hull pressure sensors, accelerometers, optical devices, shaft strain gauges) provided by SONIC project partners CETENA, Wärtsilä , University of Southampton and Newcastle University. A new semi-empirical correlation method based on Cavitating Propeller pressure fluctuation and the URN level was established. Results offer clear evidence of successfully estimating URN with on-board measurements up to the middle frequency region where the blade passing fundamental and low harmonic frequencies occur. These illuminating insights reported in this paper provide valuable benchmark sea trial data in full scale

  • HYDRO-ACOUSTIC CHARACTERIZATION OF \u201cTHE PRINCESS ROYAL\u201d Propeller AS PART OF A ROUND ROBIN TEST CAMPAIGN
    2017
    Co-Authors: Tani Giorgio, Viviani Michele, Aktas Batuhan, Atlar Mehmet
    Abstract:

    Nowadays underwater radiated noise is concerned as one of shipping detrimental emissions and so its study has gained significant importance in context of research in naval architecture. In particular, the Propeller, when Cavitating, represents the main contributor to the total noise radiated by the ship. Despite the continuous development of numerical codes for radiated noise computation, this topic is still largely studied through model scale experiments in dedicated facilities. However also this approach presents several issues to be overcome in order to achieve a consistent evaluation of Cavitating Propeller radiated noise. Model scale experiments are always affected by scale effects and for Propeller noise measurements, these regard a wide range of physical aspects. Due to this, institutes performing such activities are continuously involved in researches aimed to the enhancement of test and post-processing procedures. Furthermore, results of model scale tests, especially noise, are strongly influenced by the characteristics of the facility, by the setup adopted and the experimental procedures which should be always reported in details with results. In this context, knowledge exchange between different facilities represents an effective way to improve measurements techniques, test and post processing procedures (to be standardized as far as possible). Actually, this is one of the aims of the Noise Community of Practice of the Hydro Testing Forum (HTF). In particular, a round robin campaign has been undertaken by almost all the members regarding noise measurements for the Propeller of the \u201cPrincess Royal\u201d, based on the extensive campaign carried out at Emerson Cavitation Tunnel. In this paper tests carried out at University of Genova (UNIGE) are presented together with part of the extensive experimental campaign carried out at the Emerson Cavitation Tunnel, which was the starting point of the Round Robin campaign

Reksoprodjo H. - One of the best experts on this subject based on the ideXlab platform.

  • Cavitating Propeller flows predicted by RANS solver with structured grid and small reynolds number turbulence model approach
    2009
    Co-Authors: Sipilä T., Siikonen T., Martio J., Reksoprodjo H.
    Abstract:

    Within the EU research project VIRTUE, a Propeller is investigated in uniform and nonuniform inflow conditions by means of a RANS equation solver, FINFLO. The analyses are made in wetted and Cavitating conditions. The Propeller analyzed in this paper is the INSEAN E779A Propeller. The paper contains calculations at three different grid resolutions in wetted conditions and at the two finest grid resolutions in Cavitating conditions in uniform inflow. The mediumsize grid is used for the Propeller in nonuniform inflow simulations. The simulations are conducted on a model scale and the results are compared with the measurements and cavitation tests performed by INSEAN. The nonuniform inflow is generated by modeling the geometry of the artificial wake generator used in the cavitation tests in the calculation domain. The experimental results are published in several papers, for example in [1] and [2]. The predicted Propeller open water thrust and torque are found to be within 5 % of the measured ones. The pressure peak at the leading edge of a blade is found to be sensitive to the grid resolution. The predicted cavitation behavior of the Propeller blades is in reasonable accordance with the cavitation test observations. In uniform inflow the vaporized region is overpredicted. Contrastingly, the vaporized region is Underpredicted in the nonuniform inflow calculations. Side entrant jets could be identified in the cavity region in the nonuniform inflow simulations. The predicted vaporized regions in several blade positions together with photographs of the Cavitating Propeller are shown for comparison. The cavitation behavior trends seemed to be similar in the simulations and observations in nonuniform inflow, except that the rollup of detached sheet cavitation into a tip vortex could not be captured in the calculations. The total wake is measured between the Propeller plane and the wake generator. The predicted wake is found to be too strong, but the width of the wake is relatively close to the measurements. The Propeller loading history is shown over one Propeller revolution. It shows qualitatively reasonable trends. The loading histories of the wetted and Cavitating Propeller are almost the same due to the relative small Cavitating region in the investigated conditions. The pressure distributions at several blade positions on the suction side of the Propeller are shown in wetted and Cavitating conditions for comparison.http://deepblue.lib.umich.edu/bitstream/2027.42/84244/1/CAV2009-final45.pd