The SIMMAN 2008 workshop was held in Copenhagen, Denmark in April 2008。 The purpose of the workshop was to benchmark the prediction capabilities of different ship maneuvering simulation methods including systems- and CFD-based methods through systematic quantitative comparisons and validation against EFD data for tanker (KVLCC), container ship (KCS), and surface combatant (5415) hull form test cases。 For the KVLCC test case, two stern shape variants named KVLCC1 and KVLCC2 giving different instability loops were included。 Free model test data was compared with systems-based methods and CFD for specified free maneuvers。 Some of the systems-based methods used provided PMM and CMT data, and two used CFD instead。 CFD-based methods were used to simulate forced motions and were compared with PMM/CMT model test data。 The submissions were blind in the sense that the benchmark model test data was not provided prior to the workshop, unless data was required as input to the simulation method。 A total of 64 submissions were received for the free maneuver simulations, which included a wide range of the state-of-the-art methods in use today, such as PMM- and CMT-based methods, CFD- based methods, system identification, neural network tools and various empirical methods。 For the forced motion simulations a total of 16 submissions were received, comprising different CFD-based methods such as RANS, URANS, and DES。 This paper gives an overview of hulls, model tests, test cases, submissions, comparison results as well as the most important observations and conclusions。

Keywords: maneuvering; model testing

1。 Background

THE SIMMAN 2008 workshop was the outgrowth of discus- sions and planning conducted by the 24th and 25th ITTC Maneu-

Manuscript received at SNAME headquarters February 9, 2010; revised manuscript received October 1, 2010。

vering Committees。  The  workshop  was  the  first  of  its  kind for several reasons, primarily because maneuvering simulation methods have yet to be benchmarked for their prediction capabil- ities through systematic quantitative validation against EFD。 This benchmarking was conducted for both systems- and CFD-based methods。 Also, the international collaboration for captive and free

model  EFD  validation  data  was  noteworthy,  as  it   involved 11 ITTC institutions and 10 countries from Europe, Asia, and America。 An extensive model test campaign was performed for each of the three hulls, comprising both PMM and CMT tests in appended and bare hull conditions as well as free model tests。 Several of the tests were carried out in more than one facility。

Test cases were selected for which the participants  should make simulations。 A website was used to facilitate the workshop organization and dissemination of information and instructions to participants (www。simman2008。dk)。 Prior to the workshop, the submitted simulation results were compiled and plotted against the benchmark data。 A general reference is made to the workshop proceedings (Stern & Agdrup 2009) for further details of the methods and the comparison results。 The main characteristics  are

briefly reported here; for more details the reader should refer to Stern & Agdrup (2009)。

2。 Hulls

The hulls chosen for the workshop were those recommended as benchmark ships by the 24th ITTC。 No full-scale ships exist based on any of these hull forms。

• KVLCC: The MOERI KVLCC tanker was conceived to pro- vide data for flow physics and CFD validation for a 1997 tanker hull form with bulbous bow and transom stern。 Two stern variants were designed: KVLCC1 has barge-type stern frame lines with a fine stern end bulb, that is, relatively V-shaped  frame  lines, while  KVLCC2  has more U-shaped