On the enhancement of coupling potential flow models to RANS solvers for the prediction of propeller effective wakes

Antonio Sanchez Caja (Corresponding Author), Jussi Martio, Ilkka Saisto, T Siikonen

Research output: Contribution to journalArticleScientificpeer-review

13 Citations (Scopus)

Abstract

The calculation of the effective wake within the CFD context is usually made by combining a potential-flow method for modeling the propeller forces with a RANS equation solver for simulating the viscous flow around the hull and possible appendages. The different assumptions and/or simplifications made in the potential flow model relative to the viscous flow solver may result in significant errors in the prediction of the effective wake particularly for high loadings. This is especially troublesome for ships with full forms where large differences are expected between the nominal and effective wake, and for special propulsion applications such as contra-rotating units. Such errors are responsible within the hydrodynamic design problem for an unadjusted prediction of the propeller pitch, and within the hydrodynamic analysis problem for a deficient prediction of self-propulsion point. This paper presents an approach based on correction factors which converts propeller-induced velocities approximately estimated via potential flow theory into viscous induced velocities on the basis of a viscous flow RANS analysis. The correction factors are calculated for one reference advance number and work accurately in a neighboring region where the propeller loading may change about ±50 %. This procedure allows controlling one of the errors present in the calculation of effective wakes, namely the error derived from coupling a potential-flow method for the representation of the propeller with a RANS solver. Consequently, it permits calculating the effective wake more precisely. The approach is illustrated for a simple case in which the potential flow model representing the propeller is an actuator disk
Original languageEnglish
Pages (from-to)104-117
Number of pages13
JournalJournal of Marine Science and Technology
Volume20
Issue number1
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

Fingerprint

potential flow
Potential flow
Propellers
viscous flow
Viscous flow
prediction
Propulsion
hydrodynamics
Hydrodynamics
Actuator disks
hull
Computational fluid dynamics
Ships
modeling

Keywords

  • Coupling
  • CRP
  • effective wake
  • pod propulsor
  • potential flow
  • RANS

Cite this

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title = "On the enhancement of coupling potential flow models to RANS solvers for the prediction of propeller effective wakes",
abstract = "The calculation of the effective wake within the CFD context is usually made by combining a potential-flow method for modeling the propeller forces with a RANS equation solver for simulating the viscous flow around the hull and possible appendages. The different assumptions and/or simplifications made in the potential flow model relative to the viscous flow solver may result in significant errors in the prediction of the effective wake particularly for high loadings. This is especially troublesome for ships with full forms where large differences are expected between the nominal and effective wake, and for special propulsion applications such as contra-rotating units. Such errors are responsible within the hydrodynamic design problem for an unadjusted prediction of the propeller pitch, and within the hydrodynamic analysis problem for a deficient prediction of self-propulsion point. This paper presents an approach based on correction factors which converts propeller-induced velocities approximately estimated via potential flow theory into viscous induced velocities on the basis of a viscous flow RANS analysis. The correction factors are calculated for one reference advance number and work accurately in a neighboring region where the propeller loading may change about ±50 {\%}. This procedure allows controlling one of the errors present in the calculation of effective wakes, namely the error derived from coupling a potential-flow method for the representation of the propeller with a RANS solver. Consequently, it permits calculating the effective wake more precisely. The approach is illustrated for a simple case in which the potential flow model representing the propeller is an actuator disk",
keywords = "Coupling, CRP, effective wake, pod propulsor, potential flow, RANS",
author = "{Sanchez Caja}, Antonio and Jussi Martio and Ilkka Saisto and T Siikonen",
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year = "2014",
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On the enhancement of coupling potential flow models to RANS solvers for the prediction of propeller effective wakes. / Sanchez Caja, Antonio (Corresponding Author); Martio, Jussi; Saisto, Ilkka; Siikonen, T.

In: Journal of Marine Science and Technology, Vol. 20, No. 1, 2014, p. 104-117.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - On the enhancement of coupling potential flow models to RANS solvers for the prediction of propeller effective wakes

AU - Sanchez Caja, Antonio

AU - Martio, Jussi

AU - Saisto, Ilkka

AU - Siikonen, T

N1 - Project code: 70501 EU_TRIPOD

PY - 2014

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N2 - The calculation of the effective wake within the CFD context is usually made by combining a potential-flow method for modeling the propeller forces with a RANS equation solver for simulating the viscous flow around the hull and possible appendages. The different assumptions and/or simplifications made in the potential flow model relative to the viscous flow solver may result in significant errors in the prediction of the effective wake particularly for high loadings. This is especially troublesome for ships with full forms where large differences are expected between the nominal and effective wake, and for special propulsion applications such as contra-rotating units. Such errors are responsible within the hydrodynamic design problem for an unadjusted prediction of the propeller pitch, and within the hydrodynamic analysis problem for a deficient prediction of self-propulsion point. This paper presents an approach based on correction factors which converts propeller-induced velocities approximately estimated via potential flow theory into viscous induced velocities on the basis of a viscous flow RANS analysis. The correction factors are calculated for one reference advance number and work accurately in a neighboring region where the propeller loading may change about ±50 %. This procedure allows controlling one of the errors present in the calculation of effective wakes, namely the error derived from coupling a potential-flow method for the representation of the propeller with a RANS solver. Consequently, it permits calculating the effective wake more precisely. The approach is illustrated for a simple case in which the potential flow model representing the propeller is an actuator disk

AB - The calculation of the effective wake within the CFD context is usually made by combining a potential-flow method for modeling the propeller forces with a RANS equation solver for simulating the viscous flow around the hull and possible appendages. The different assumptions and/or simplifications made in the potential flow model relative to the viscous flow solver may result in significant errors in the prediction of the effective wake particularly for high loadings. This is especially troublesome for ships with full forms where large differences are expected between the nominal and effective wake, and for special propulsion applications such as contra-rotating units. Such errors are responsible within the hydrodynamic design problem for an unadjusted prediction of the propeller pitch, and within the hydrodynamic analysis problem for a deficient prediction of self-propulsion point. This paper presents an approach based on correction factors which converts propeller-induced velocities approximately estimated via potential flow theory into viscous induced velocities on the basis of a viscous flow RANS analysis. The correction factors are calculated for one reference advance number and work accurately in a neighboring region where the propeller loading may change about ±50 %. This procedure allows controlling one of the errors present in the calculation of effective wakes, namely the error derived from coupling a potential-flow method for the representation of the propeller with a RANS solver. Consequently, it permits calculating the effective wake more precisely. The approach is illustrated for a simple case in which the potential flow model representing the propeller is an actuator disk

KW - Coupling

KW - CRP

KW - effective wake

KW - pod propulsor

KW - potential flow

KW - RANS

U2 - 10.1007/s00773-014-0255-4

DO - 10.1007/s00773-014-0255-4

M3 - Article

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JO - Journal of Marine Science and Technology

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SN - 0948-4280

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ER -