1.
Frans Hendrik Lafeber, Thomas Lloyd; Bosschers, Johan
Inter.Noise Hongkong 27-30 August, no. ID682, 2017.
@conference{Lafeber2017b,
title = {Validation of underwater radiated noise predictions for a merchant vessel using full-scale measurements},
author = {Frans Hendrik Lafeber, Thomas Lloyd and Johan Bosschers},
url = {http://www.marin.nl/web/Publications/Publication-items/Validation-of-underwater-radiated-noise-predictions-for-a-merchant-vessel-using-fullscale-measurements.htm},
year = {2017},
date = {2017-08-27},
booktitle = {Inter.Noise Hongkong 27-30 August},
number = {ID682},
abstract = {Underwater radiated noise (URN) was previously primarily of interest in connection with the signature of naval vessels. Recently it has become increasingly relevant for other vessel types, such as cruise and merchant ships, due to a growing concern that marine life is affected by rising anthropogenic noise levels in the oceans. Shipping is a main contributor to those noise levels, with the cavitating propeller being the dominant noise source. Marine mammals and fish use sound to communicate and to sense their environment and this requires low background noise levels. The URN of a cavitating propeller can be predicted before the ship is built by means of computations and model-scale tests. High-quality validation material is needed for the validation of computational models and model test procedures, which include the scaling of the noise levels. Within the CRS framework (Cooperative Research Ships, http://www.crships.org/) a full-scale measurement campaign was carried out on a single-screw cargo vessel by DNV-GL, DAMEN and MARIN. Model tests for several conditions have been carried out in MARIN’s Depressurized Wave Basin. During these tests, URN was measured and cavitation patterns were observed using high-speed video cameras. Within the CRS a semi-empirical model has also been developed, which predicts the broadband pressure fluctuations and URN of cavitating tip vortices on marine propellers. This paper discusses a validation study of the computational and model test procedures for determining URN due to cavitating propellers, using the full-scale data of the aforementioned ship. Some aspects of the analysis and scaling procedures are discussed. Results are shown for three pitch settings. The agreement between the results of the various methods is very good; mostly within 3 dB. The change in noise levels between the three tested conditions is well captured.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Underwater radiated noise (URN) was previously primarily of interest in connection with the signature of naval vessels. Recently it has become increasingly relevant for other vessel types, such as cruise and merchant ships, due to a growing concern that marine life is affected by rising anthropogenic noise levels in the oceans. Shipping is a main contributor to those noise levels, with the cavitating propeller being the dominant noise source. Marine mammals and fish use sound to communicate and to sense their environment and this requires low background noise levels. The URN of a cavitating propeller can be predicted before the ship is built by means of computations and model-scale tests. High-quality validation material is needed for the validation of computational models and model test procedures, which include the scaling of the noise levels. Within the CRS framework (Cooperative Research Ships, http://www.crships.org/) a full-scale measurement campaign was carried out on a single-screw cargo vessel by DNV-GL, DAMEN and MARIN. Model tests for several conditions have been carried out in MARIN’s Depressurized Wave Basin. During these tests, URN was measured and cavitation patterns were observed using high-speed video cameras. Within the CRS a semi-empirical model has also been developed, which predicts the broadband pressure fluctuations and URN of cavitating tip vortices on marine propellers. This paper discusses a validation study of the computational and model test procedures for determining URN due to cavitating propellers, using the full-scale data of the aforementioned ship. Some aspects of the analysis and scaling procedures are discussed. Results are shown for three pitch settings. The agreement between the results of the various methods is very good; mostly within 3 dB. The change in noise levels between the three tested conditions is well captured.
2.
Bosschers, Johan
Fifth International Symposium on Marine Propulsors smp’17, 2017.
@conference{Bosschers2017,
title = {A Semi-Empirical Method to Predict Broadband Hull Pressure Fluctuations and Underwater Radiated Noise by Cavitating Tip Vortices},
author = {Johan Bosschers},
url = {http://www.marin.nl/web/Publications/Publication-items/A-SemiEmpirical-Method-to-Predict-Broadband-Hull-Pressure-Fluctuations-and-Underwater-Radiated-Noise-by-Cavitating-Tip-Vortices.htm},
year = {2017},
date = {2017-06-01},
booktitle = {Fifth International Symposium on Marine Propulsors smp’17},
abstract = {A semi-empirical method is presented that predicts broadband hull pressure fluctuations and underwater radiated noise due to propeller tip vortex cavitation. The method uses a hump-shaped pattern for the spectrum and it predicts the center frequency and level of this hump. The principal parameter is the vortex cavity size which is predicted using a combination of a boundary element method and a semi-empirical vortex model. It is shown that such a model is able to well represent the variation of cavity size with cavitation number. Using a database of model-scale and full-scale measured hull pressure data, an empirical formulation for the center frequency and level has been developed that is a function of among others the cavity size. Predicted and measured hull pressure and radiated noise spectra are compared for various cases. Acceptable results are obtained but the comparison also shows differences that require adjustments of parameters which need to be further investigated. },
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
A semi-empirical method is presented that predicts broadband hull pressure fluctuations and underwater radiated noise due to propeller tip vortex cavitation. The method uses a hump-shaped pattern for the spectrum and it predicts the center frequency and level of this hump. The principal parameter is the vortex cavity size which is predicted using a combination of a boundary element method and a semi-empirical vortex model. It is shown that such a model is able to well represent the variation of cavity size with cavitation number. Using a database of model-scale and full-scale measured hull pressure data, an empirical formulation for the center frequency and level has been developed that is a function of among others the cavity size. Predicted and measured hull pressure and radiated noise spectra are compared for various cases. Acceptable results are obtained but the comparison also shows differences that require adjustments of parameters which need to be further investigated.
3.
Lafeber, Frans Hendrik; Lloyd, Thomas
Round Robin test on the underwater radiated noise of a cavitating ship propeller in open water Conference
The 5th international conference on advanced model measurements technology (AMT '17) 11/13-10-2017, 2017.
@conference{Lafeber2017,
title = {Round Robin test on the underwater radiated noise of a cavitating ship propeller in open water},
author = {Frans Hendrik Lafeber and Thomas Lloyd},
url = {http://www.marin.nl/web/Publications/Publication-items/Round-Robin-test-on-the-underwater-radiated-noise-of-a-cavitating-ship-propeller-in-open-water.htm},
year = {2017},
date = {2017-01-11},
booktitle = {The 5th international conference on advanced model measurements technology (AMT '17) 11/13-10-2017},
abstract = {Due to concerns about its effect on marine life, shipping noise is receiving increasing attention within the maritime industry. The primary noise source is known to be the cavitating propeller. In order to check compliance with class rules and upcoming environmental regulations, underwater radiated noise can be predicted during the design of a vessel using model-scale measurements, such as those performed at MARIN’s Depressurized Wave Basin. As a means to better understand the accuracy and reliability of underwater radiated noise measurements, a round robin test campaign was organised within the Community-of-Practice Noise of the HydroTesting Forum, with the aim of comparing results between several institutes for an open water propeller test setup. This paper reports the test campaign carried out at MARIN, including details of the experimental setup, data analysis methods and resulting noise levels. Noise was measured using a hydrophone fixed on a bottom-mounted mast, with a dedicated silent towing carriage used to minimise background noise. The effect of applying electrolysis as a means to improve cavitation inception was investigated, and found to be more important for high cavitation numbers. Differences in the radiated noise levels between different test conditions were found to depend largely on the dynamics of the cavitating tip vortex. In general a primary broadband hump was seen, the frequency of which is affected by propeller loading and cavitation number. The spectral shape at higher frequencies could not so easily be related to a clear physical origin however. Following further data analysis, the results will be compared to those from the other participants in the round robin test campaign.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Due to concerns about its effect on marine life, shipping noise is receiving increasing attention within the maritime industry. The primary noise source is known to be the cavitating propeller. In order to check compliance with class rules and upcoming environmental regulations, underwater radiated noise can be predicted during the design of a vessel using model-scale measurements, such as those performed at MARIN’s Depressurized Wave Basin. As a means to better understand the accuracy and reliability of underwater radiated noise measurements, a round robin test campaign was organised within the Community-of-Practice Noise of the HydroTesting Forum, with the aim of comparing results between several institutes for an open water propeller test setup. This paper reports the test campaign carried out at MARIN, including details of the experimental setup, data analysis methods and resulting noise levels. Noise was measured using a hydrophone fixed on a bottom-mounted mast, with a dedicated silent towing carriage used to minimise background noise. The effect of applying electrolysis as a means to improve cavitation inception was investigated, and found to be more important for high cavitation numbers. Differences in the radiated noise levels between different test conditions were found to depend largely on the dynamics of the cavitating tip vortex. In general a primary broadband hump was seen, the frequency of which is affected by propeller loading and cavitation number. The spectral shape at higher frequencies could not so easily be related to a clear physical origin however. Following further data analysis, the results will be compared to those from the other participants in the round robin test campaign.
4.
Lafeber, Frans Hendrik; Bosschers, Johan
13th International Symposium on Practical Design of Ships (PRADS), Copenhagen, Denmark, no. ID105, 2016.
@conference{Lafeber2016,
title = {Validation of computational and experimental prediction methods for the underwater radiated noise of a small research vessel},
author = {Frans Hendrik Lafeber and Johan Bosschers},
url = {http://www.marin.nl/web/Publications/Papers/Validation-of-computational-and-experimental-prediction-methods-for-the-underwater-radiated-noise-of-a-small-research-vessel.htm},
year = {2016},
date = {2016-09-04},
booktitle = {13th International Symposium on Practical Design of Ships (PRADS), Copenhagen, Denmark},
number = {ID105},
abstract = {The underwater radiated noise of a small research vessel, The Princess Royal, has been predicted using computational methods and model tests and has been compared to full-scale data. For the model tests, a correction for the Lloyd’s mirror effect has been implemented in the analysis. The results are then compared to data from full-scale measurements. After correcting for the viscous scale effects on vortex cavitation, there is a good agreement between the model tests and full scale at the lowest speed. For the higher speeds (more cavita-tion), the agreement is good at the low and high frequency range, but there is a difference of about 10 dB between the model tests and full scale at mid frequency range.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
The underwater radiated noise of a small research vessel, The Princess Royal, has been predicted using computational methods and model tests and has been compared to full-scale data. For the model tests, a correction for the Lloyd’s mirror effect has been implemented in the analysis. The results are then compared to data from full-scale measurements. After correcting for the viscous scale effects on vortex cavitation, there is a good agreement between the model tests and full scale at the lowest speed. For the higher speeds (more cavita-tion), the agreement is good at the low and high frequency range, but there is a difference of about 10 dB between the model tests and full scale at mid frequency range.
2017
Frans Hendrik Lafeber, Thomas Lloyd; Bosschers, Johan
Inter.Noise Hongkong 27-30 August, no. ID682, 2017.
Abstract | Links | BibTeX | Tags: cavitating propellers, underwater radiated noise, validation study
@conference{Lafeber2017b,
title = {Validation of underwater radiated noise predictions for a merchant vessel using full-scale measurements},
author = {Frans Hendrik Lafeber, Thomas Lloyd and Johan Bosschers},
url = {http://www.marin.nl/web/Publications/Publication-items/Validation-of-underwater-radiated-noise-predictions-for-a-merchant-vessel-using-fullscale-measurements.htm},
year = {2017},
date = {2017-08-27},
booktitle = {Inter.Noise Hongkong 27-30 August},
number = {ID682},
abstract = {Underwater radiated noise (URN) was previously primarily of interest in connection with the signature of naval vessels. Recently it has become increasingly relevant for other vessel types, such as cruise and merchant ships, due to a growing concern that marine life is affected by rising anthropogenic noise levels in the oceans. Shipping is a main contributor to those noise levels, with the cavitating propeller being the dominant noise source. Marine mammals and fish use sound to communicate and to sense their environment and this requires low background noise levels. The URN of a cavitating propeller can be predicted before the ship is built by means of computations and model-scale tests. High-quality validation material is needed for the validation of computational models and model test procedures, which include the scaling of the noise levels. Within the CRS framework (Cooperative Research Ships, http://www.crships.org/) a full-scale measurement campaign was carried out on a single-screw cargo vessel by DNV-GL, DAMEN and MARIN. Model tests for several conditions have been carried out in MARIN’s Depressurized Wave Basin. During these tests, URN was measured and cavitation patterns were observed using high-speed video cameras. Within the CRS a semi-empirical model has also been developed, which predicts the broadband pressure fluctuations and URN of cavitating tip vortices on marine propellers. This paper discusses a validation study of the computational and model test procedures for determining URN due to cavitating propellers, using the full-scale data of the aforementioned ship. Some aspects of the analysis and scaling procedures are discussed. Results are shown for three pitch settings. The agreement between the results of the various methods is very good; mostly within 3 dB. The change in noise levels between the three tested conditions is well captured.},
keywords = {cavitating propellers, underwater radiated noise, validation study},
pubstate = {published},
tppubtype = {conference}
}
Underwater radiated noise (URN) was previously primarily of interest in connection with the signature of naval vessels. Recently it has become increasingly relevant for other vessel types, such as cruise and merchant ships, due to a growing concern that marine life is affected by rising anthropogenic noise levels in the oceans. Shipping is a main contributor to those noise levels, with the cavitating propeller being the dominant noise source. Marine mammals and fish use sound to communicate and to sense their environment and this requires low background noise levels. The URN of a cavitating propeller can be predicted before the ship is built by means of computations and model-scale tests. High-quality validation material is needed for the validation of computational models and model test procedures, which include the scaling of the noise levels. Within the CRS framework (Cooperative Research Ships, http://www.crships.org/) a full-scale measurement campaign was carried out on a single-screw cargo vessel by DNV-GL, DAMEN and MARIN. Model tests for several conditions have been carried out in MARIN’s Depressurized Wave Basin. During these tests, URN was measured and cavitation patterns were observed using high-speed video cameras. Within the CRS a semi-empirical model has also been developed, which predicts the broadband pressure fluctuations and URN of cavitating tip vortices on marine propellers. This paper discusses a validation study of the computational and model test procedures for determining URN due to cavitating propellers, using the full-scale data of the aforementioned ship. Some aspects of the analysis and scaling procedures are discussed. Results are shown for three pitch settings. The agreement between the results of the various methods is very good; mostly within 3 dB. The change in noise levels between the three tested conditions is well captured.
Bosschers, Johan
Fifth International Symposium on Marine Propulsors smp’17, 2017.
Abstract | Links | BibTeX | Tags: cavitation, hull pressures, propeller, tip vortex, underwater radiated noise
@conference{Bosschers2017,
title = {A Semi-Empirical Method to Predict Broadband Hull Pressure Fluctuations and Underwater Radiated Noise by Cavitating Tip Vortices},
author = {Johan Bosschers},
url = {http://www.marin.nl/web/Publications/Publication-items/A-SemiEmpirical-Method-to-Predict-Broadband-Hull-Pressure-Fluctuations-and-Underwater-Radiated-Noise-by-Cavitating-Tip-Vortices.htm},
year = {2017},
date = {2017-06-01},
booktitle = {Fifth International Symposium on Marine Propulsors smp’17},
abstract = {A semi-empirical method is presented that predicts broadband hull pressure fluctuations and underwater radiated noise due to propeller tip vortex cavitation. The method uses a hump-shaped pattern for the spectrum and it predicts the center frequency and level of this hump. The principal parameter is the vortex cavity size which is predicted using a combination of a boundary element method and a semi-empirical vortex model. It is shown that such a model is able to well represent the variation of cavity size with cavitation number. Using a database of model-scale and full-scale measured hull pressure data, an empirical formulation for the center frequency and level has been developed that is a function of among others the cavity size. Predicted and measured hull pressure and radiated noise spectra are compared for various cases. Acceptable results are obtained but the comparison also shows differences that require adjustments of parameters which need to be further investigated. },
keywords = {cavitation, hull pressures, propeller, tip vortex, underwater radiated noise},
pubstate = {published},
tppubtype = {conference}
}
A semi-empirical method is presented that predicts broadband hull pressure fluctuations and underwater radiated noise due to propeller tip vortex cavitation. The method uses a hump-shaped pattern for the spectrum and it predicts the center frequency and level of this hump. The principal parameter is the vortex cavity size which is predicted using a combination of a boundary element method and a semi-empirical vortex model. It is shown that such a model is able to well represent the variation of cavity size with cavitation number. Using a database of model-scale and full-scale measured hull pressure data, an empirical formulation for the center frequency and level has been developed that is a function of among others the cavity size. Predicted and measured hull pressure and radiated noise spectra are compared for various cases. Acceptable results are obtained but the comparison also shows differences that require adjustments of parameters which need to be further investigated.
Lafeber, Frans Hendrik; Lloyd, Thomas
Round Robin test on the underwater radiated noise of a cavitating ship propeller in open water Conference
The 5th international conference on advanced model measurements technology (AMT '17) 11/13-10-2017, 2017.
Abstract | Links | BibTeX | Tags: Depressurized Wave Basin, shipping noise, underwater radiated noise
@conference{Lafeber2017,
title = {Round Robin test on the underwater radiated noise of a cavitating ship propeller in open water},
author = {Frans Hendrik Lafeber and Thomas Lloyd},
url = {http://www.marin.nl/web/Publications/Publication-items/Round-Robin-test-on-the-underwater-radiated-noise-of-a-cavitating-ship-propeller-in-open-water.htm},
year = {2017},
date = {2017-01-11},
booktitle = {The 5th international conference on advanced model measurements technology (AMT '17) 11/13-10-2017},
abstract = {Due to concerns about its effect on marine life, shipping noise is receiving increasing attention within the maritime industry. The primary noise source is known to be the cavitating propeller. In order to check compliance with class rules and upcoming environmental regulations, underwater radiated noise can be predicted during the design of a vessel using model-scale measurements, such as those performed at MARIN’s Depressurized Wave Basin. As a means to better understand the accuracy and reliability of underwater radiated noise measurements, a round robin test campaign was organised within the Community-of-Practice Noise of the HydroTesting Forum, with the aim of comparing results between several institutes for an open water propeller test setup. This paper reports the test campaign carried out at MARIN, including details of the experimental setup, data analysis methods and resulting noise levels. Noise was measured using a hydrophone fixed on a bottom-mounted mast, with a dedicated silent towing carriage used to minimise background noise. The effect of applying electrolysis as a means to improve cavitation inception was investigated, and found to be more important for high cavitation numbers. Differences in the radiated noise levels between different test conditions were found to depend largely on the dynamics of the cavitating tip vortex. In general a primary broadband hump was seen, the frequency of which is affected by propeller loading and cavitation number. The spectral shape at higher frequencies could not so easily be related to a clear physical origin however. Following further data analysis, the results will be compared to those from the other participants in the round robin test campaign.},
keywords = {Depressurized Wave Basin, shipping noise, underwater radiated noise},
pubstate = {published},
tppubtype = {conference}
}
Due to concerns about its effect on marine life, shipping noise is receiving increasing attention within the maritime industry. The primary noise source is known to be the cavitating propeller. In order to check compliance with class rules and upcoming environmental regulations, underwater radiated noise can be predicted during the design of a vessel using model-scale measurements, such as those performed at MARIN’s Depressurized Wave Basin. As a means to better understand the accuracy and reliability of underwater radiated noise measurements, a round robin test campaign was organised within the Community-of-Practice Noise of the HydroTesting Forum, with the aim of comparing results between several institutes for an open water propeller test setup. This paper reports the test campaign carried out at MARIN, including details of the experimental setup, data analysis methods and resulting noise levels. Noise was measured using a hydrophone fixed on a bottom-mounted mast, with a dedicated silent towing carriage used to minimise background noise. The effect of applying electrolysis as a means to improve cavitation inception was investigated, and found to be more important for high cavitation numbers. Differences in the radiated noise levels between different test conditions were found to depend largely on the dynamics of the cavitating tip vortex. In general a primary broadband hump was seen, the frequency of which is affected by propeller loading and cavitation number. The spectral shape at higher frequencies could not so easily be related to a clear physical origin however. Following further data analysis, the results will be compared to those from the other participants in the round robin test campaign.
2016
Lafeber, Frans Hendrik; Bosschers, Johan
13th International Symposium on Practical Design of Ships (PRADS), Copenhagen, Denmark, no. ID105, 2016.
Abstract | Links | BibTeX | Tags: cavitation, computations, model tests, propeller, underwater radiated noise
@conference{Lafeber2016,
title = {Validation of computational and experimental prediction methods for the underwater radiated noise of a small research vessel},
author = {Frans Hendrik Lafeber and Johan Bosschers},
url = {http://www.marin.nl/web/Publications/Papers/Validation-of-computational-and-experimental-prediction-methods-for-the-underwater-radiated-noise-of-a-small-research-vessel.htm},
year = {2016},
date = {2016-09-04},
booktitle = {13th International Symposium on Practical Design of Ships (PRADS), Copenhagen, Denmark},
number = {ID105},
abstract = {The underwater radiated noise of a small research vessel, The Princess Royal, has been predicted using computational methods and model tests and has been compared to full-scale data. For the model tests, a correction for the Lloyd’s mirror effect has been implemented in the analysis. The results are then compared to data from full-scale measurements. After correcting for the viscous scale effects on vortex cavitation, there is a good agreement between the model tests and full scale at the lowest speed. For the higher speeds (more cavita-tion), the agreement is good at the low and high frequency range, but there is a difference of about 10 dB between the model tests and full scale at mid frequency range.},
keywords = {cavitation, computations, model tests, propeller, underwater radiated noise},
pubstate = {published},
tppubtype = {conference}
}
The underwater radiated noise of a small research vessel, The Princess Royal, has been predicted using computational methods and model tests and has been compared to full-scale data. For the model tests, a correction for the Lloyd’s mirror effect has been implemented in the analysis. The results are then compared to data from full-scale measurements. After correcting for the viscous scale effects on vortex cavitation, there is a good agreement between the model tests and full scale at the lowest speed. For the higher speeds (more cavita-tion), the agreement is good at the low and high frequency range, but there is a difference of about 10 dB between the model tests and full scale at mid frequency range.