Michael Schmiechen, Berlin
News on propulsion

Contents

• Very happy end of a very long 'story'
• METEOR-Festschrift and further
• Earlier input

Note: Rational theory of propulsion

For some years my work on the theory of trials and monitoring of ship propulsion
has been so intense, that all of the results have been published in the 'News flash',
while this Section has not been updated.

In order to remedy this unsatisfactory situation the following material has been
shifted from the 'News flash.

Last update and additions: 2019.05.22

Very happy end of a very long 'story'

The whole long (hi)story is documented in the Section
'News on powering trials'. The title of the present
subsection of the 'News flash' story, has evidently
been chosen prematurely. As the following entries show,
there may be no end to that story.

Further promoting quasi-steady ship powering tests

After all the worksheets mod_6_trial_rev6 and mod_9_trial_rev6,
concerning the identification of the partial efficiencies without
reference to the thrust values measured on model scale, have
reached their state of maturity after final corrections and
additions urged by Dr. Klaus Wagner.

Last updates and additions: 2019.01.29


Further to promote quasi-steady model and ship powering tests and
to establish a transparent, sound basis for further research I have
undertaken 'another' rigorous revision of my quasi-steady model test
of 1986. Eliminating stupid mistakes and clumsy, though enlightning
detours I arrived mostly at the same results as before.

The worksheets of my sixth revision in PTC Mathcad 15.0 are superseding
all previous versions and are published here for discussion:


• A title page
  
• Rule driven symbols developed
  
• Model data, test conditions
  
• Numerical routines developed
  
• Data of quasi-steady model trial
  
• Quasi-stationary states identified
  
• Propulsive efficiency etc identified
  
• Partial efficiencies identified: 'model test'
  
• Traditional vs. rational results: model test
  
• Partial efficiencies identified: 'ship trial'
  
  The file mod_9_trial_rev6, the identification of the partial efficiencies
  without reference to the thrust values measured on model scale, has finally
  also reached a state of maturity.
  
  Mistakes, more or less serious, are taken care of as soon as detected.
  Hence do not rely on outdated copies of the worksheets!
  
  Last updates and additions: 2018.08.19/2018.11.01/2019.01.29
  
  
  
  Different from my former evaluations as 'model trial' I took advantage
  of the thrust values measured during the 'test'. In a second file, denoted
  'trial', I have shown, that the same results are obtained without reference
  to thrust values, being not available on full scale.
  
  The final step will be to 'repeat' the quasi-steady tests of 1988 with the
  German research vessel METEOR, though without measurement of the
  thrust and any other extra instrumentation and prior information.
  Repeatedly I have invited young colleagues to earn a doctor's hat,
  but the 'dogs' want to be carried to the hunt.
  
  PS: Two remarks may be helpful.
  
  Firstly, model powering tests are conducted with a frictional deduction
  for the purpose of powering predictions, not (!) for the analysis of the
  model powering performance. Their unresolved inherent problem is,
  that the frictional deduction does not scale the propeller inflow.
  
  Secondly, any wake fractions identified are nominal values, that cannot
  be measured. The propeller behind the hull and the equivalent propeller
  conceptually far behind the hull, outside its displacements effect, are
  thus more adequately considered as pumps. I have used this conception
  successfully to design an energy wake adapted ducted propulsor,
  treating all interactions implictly as usual in pump design.
  
  Last update and revisions: 2018.05.07.
  

The advanced analysis of my 'model' trial further advanced!
Evident prejudices, mistakes and bugs hopefully eliminated!

The continued rigorous scrutiny of Dr. Klaus Wagner and of Daniel Wiens
has triggered a rigorous revision of my former evaluation of the 'model'
trial, I had performed in 1986 before the METEOR tests of 1988, to
demonstrate the feasibility and efficiency of quasi-steady trials.

For ready reference and for the benefit of colleagues working on related
problems, applications on model and ship scale in particular, I had
published at this stage of my ongoing research the latest versions of
all my worksheets, not only the last two (no longer three) final files,
concerning the identification of the values of hull propeller interactions
and partial efficiencies.

The apparently 'much too good' solution presented earlier has of course been
perfectly correct! On model scale the thrust can be measured and is being
measured. Thus the values of the thrust deduction fraction could be identified
directly from the data acquired during the quasi-steady 'model' trial and those
of the wake fraction and other magnitudes have been obtained by iteration.

The remaining problem, to identify the values of the hull-propeller
interactions without reference to the results of thrust measurements
does not exist on model scale, but only on ship scale, where reliable
values of the thrust cannot be obtained in practice.

The solution of this 'last' problem of my rational approach turned out
to be much simpler than expected and is demonstrated in every detail
in the pertinent worksheet mod_7_hpi.

A detailed explanatory paper, concerning the approach and the results
obtained so far and on problems to be solved next, will be published
in due course.

For the 30th ATTC, to be held at the NSWC Carderock in early
October 2017, a leaflet has been prepared, repeating
• Some executive abstracts.
  
  Last update and revisions: 2017.04.14/15/27, 2018.03.03.
  

METEOR-Festschrift and further

The following is a

• Contribution to the presentation
  of 'A rational method to quantify the aging of ship hulls and propellers'
  by Dr.-Ing. habil. Klaus Wagner held at the Lehrstuhl für Schiffbau
  of the University Rostock, also viewed at the corresponding institutes
  at Hamburg, Duisburg and Berlin.
  
  Last update and revisions: 2016.11.26.
  

The advanced analysis of the 'model' trial further advanced!

Continuing discussions with Daniel Wiens have lead to further corrections
and improvements of the 'final' files.

As before the whole programme has conveniently been broken down into
a series of PTC Mathcad 15.0 worksheets, each devoted to a fundamental
step of the whole straightforward procedure of powering prediction
based on quasi-steady model tests.

As it turned out, the former three last files contained a number of
prejudices, mistakes and bugs, which have been eliminated in the 'last'
update, to be found at the beginning of the 'News flash'.

Last update and revisions: 2016.07.29./2017.04.14


In the meantime I have spread the 'gospel' as documented in the
• Correspondence concerning the revision,
  alerting the Members of the pertinent 28thITTC Committees and informing
  colleagues and friends of the rational theory of trials and monitoring of ship
  powering performance.
  
  For ready reference I have added
• An executive abstract,
  drafted in response to further critical questions by Dr. Klaus Wagner,
  and the derivation and approximation of
• The thrust deduction theorem,
  taking advantage of the features of symbolic Maple implemented in Mathcad,
  first published as a lecture note in 1997.
  
  Last update and revisions: 2016.07.03.
  
  
  Following corrections, improvements and additions of its draft
  the 'final'version of
  
• the third volume
of the METEOR-Festschrift has now been published.

For ready reference links to the two volumes published earlier, in 2014
and 2013, respectively, are provided here as well:
• the second volume,
• the first volume.

And, of interest to managers and other readers in a hurry,
two leaflets concerning the volumes of the Festschrift,
which have been published earlier and distributed widely,
may be accessed here:
• concerning traditonal trials,
• concerning the 'model' test.

Last update and additions: 2017.02.08

Earlier input

Rational theory of propulsion:
not so 'recent' interest (2012).

A request of Prof. Naoji Toki concerning quasi-steady propulsion tests
on model scale has triggerd the following sketch of
• the basic ideas
  underlying the developments of the various branches of the rational theory
  of propulsion.
  
  Last update and additions: 2012.01.11
  
  

Rational theory of propulsion:
Summary of developments:
forthcoming presentations

• The announcement
  of lectures covering the latest developments and future pertinent tasks
  found no response among the students of naval architecture at TUB.
  
  But the author continues to spread the gospel. Based on the lectures
  held at the VWS Jubilee in November 2003 and at the 100. Annual Meeting of STG
  in November 2005 and at NSTL Visakhapatnam in January 2006 the following lecture
• Beiträge zur Theorie der Propulsion: (zu) lang
  on future developments in theory of propulsion
  has been held at the University Rostock on January 10, 2008
  and a shorter, condensed presentation
• Beiträge zur Theorie der Propulsion: gestrafft
  has subsequently been delivered at the Technical University Berlin
  on February 08, 2008.
  
  Abstract of the lectures under the subtitle 'Erinnerungen an die Zukunft':
  
  'Leitendes Prinzip meiner Arbeiten, nicht nur zur Schiffstheorie, war und
  ist das dictum von Albert Einstein: 'Probleme kann man niemals mit der
  gleichen Denkweise lösen, durch die sie entstanden sind.' Als Beispiele
  dienen: die Auswertung traditioneller Probefahrten, diverse Aspekte der
  Strahltheorie und ihrer Anwendung auf den Entwurf von Düsen-Propellern
  im Nachstrom und die axiomatische Theorie der Wechselwirkungen und ihrer
  Anwendung auf die Auswertung quasi-stationärer Betriebszustände bei
  Modellen und Schiffen. Dabei geht es nicht um persönliche Anekdoten,
  sondern um Geschichte und Geschichten, die nicht in den Berichten
  stehen, um Fakten zur Entstehung, Entwicklung und Zukunft von Ideen,
  also zur Entwicklung der Schiffstheorie.'
  
  In order to reach colleagues in the United States the author has drafted
  the abstract of a paper proposed for presentation at the forthcoming
  Annual Meeting of SNAME to be held at Houston, Texas, October 14-17, 2008.
  In response the author has received the following mail:
  
  "The SNAME Papers Committee regrets to advise you that the abstract
  that you submitted for a presentation at the upcoming Annual Meeting,
  the SNAME Marine Technology Conference 2008, has not been accepted.
  The members of the Committee thank you for the opportunity to consider
  the abstract, but they consider that the material may not be appropriate
  for this forum."
  
  

Paper and presentation at the Symposium
on Marine Propulsors at Trondheim SMP'09

The author's request for information on recent developments
on the rational theory of propulsion, of ship speed trials
in particular, resulted in a discussion with Dr. Hollenbach
pending to be published here for documentary purposes and
for ready reference in connection with recent discussions
on the subject with Dr. Klaus Wagner, Friedrich Mewis
and Prof. Som Sharma.

Last update and additions: 2013.02.07

In the meantime the closely related
• Abstract of a paper
  on 'Recent Results and Perspectives' after
  '50 Years Rational Theory of Propulsion'
  proposed for presentation at the forthcoming
  'First International Symposium on Marine Propulsors',
  to be held at Trondheim, Norway, June 22-24, 2009,
  has been accepted.
  
  In preparing the paper the author in a
• Request for contributions
  asks colleagues to contribute their experiences
  with the procedures proposed
  for evaluating traditional and quasi-steady trials,
  on model scale and as well as on full scale,
  and designing and evaluating ducted propulsors,
  wake adapted and hull integrated in particular.
  
  In the meantime the
• Text of the paper
  has been accepted by the organisers and updated
  to account for the following study into the
• Merits of propulsors.
  
  For ready reference a preprint of the chapter on
• 'Propulsion mechanics'
  in 'Classical mechanics reconstructed', the opus
  magnum of the author to be published shortly,
  is also being provided. Details on this project
  are to be found under 'News on mechanics'.
  
  In updating and extending this chapter a mistake in the study
  into the merits of propulsors has been detected and corrected.
  
  The paper and its
• Presentation
  have been published on 2009.04.15 here for written discussions,
  which together with the oral discussions at the Symposium at Trondheim,
  were intended be documented in a separate paper.
  
  But no written discussions have been submitted and the five minutes allotted
  for oral discussions were not sufficient for any substantial contributions.
  
  The following mail concerning the
  
• Quasi-steady test technique
  developed at MARIN may be considered as a, the first contribution
  to the discussion.
  
  Last update and additions: 2010.01.04
  
  

A 'model test'

In a seminar at the Gdansk Ship Model Basin on January 16-18, 2002,
not only the evaluation of ship speed trials but of ship model tests
has been treated in detail. While the rational evaluation
of traditional trials has 'nothing to do' with ship theory,
but is a matter of elementary mechanics and craftmanship,
the rational evaluation of the ship powering performance
on model and full scale requires some ship theory as well as
additional thrust measurements at quasi-steady conditions.

To demonstrate the potential of methodology the re-evaluation of

• A quasisteady model test
  has been undertaken, which has been published earlier
  in 'Wake and Thrust Deduction from Quasisteady
  Ship Model Propulsion Tests Alone' on occasion of a visit
  to Korean and Japanese ship research institutes
  and the 18th ITTC at Kobe in October 1987
  in commemoration of the 4th ITTC at Berlin in 1937.
  This paper is identical with VWS Report No. 1100/87,
  from which the following
  
• Copies of the essential parts
  have been taken. Warning: The file is very large, nearly 1MB.
  
  The goal was to study the impact of the insights gained
  over the past fifteen years and to provide an adequate basis
  for the development of a rational scaling procedure,
  which has been felt missing in the discussions at Gdansk.
  During this work the document on
  
• Local wake axioms
  including the re-evaluation of the METEOR data has been updated.
  
  In the meantime misprints have been corrected, replacing 'wake fraction'
  for 'thrust deduction fraction' in three subtitles, and replacing
  the hydraulic efficiency etaJP by the correct jet efficiency etaTJ
  under the subheading MS0202201000.
  
  
  The problems in all these exercises have been the local wake axioms.
  Triggered by questions and continued discussions with Dr.-Ing. habil.
  Klaus Wagner of Rostock conceptual and numerical exercises have lead
  to the final clarification of the procedure. In the process of clarification
  a number of alternative approaches have been designed and tested,
  but after much deliberation all of them have been discarded.
  
  The central problem identified is the axiom concerning the stationarity of the
  hydraulic efficiency in the small range investigated. This axiom, a condition
  limiting the complexity of the model, has been adopted to get along with only
  two parameters to be identified in a robust procedure.
  
  Consequently this condition has been provided for by appropriate selection
  of the range investigated in
• The 'model test': final analysis.
  The procedure is explained in detail and is after all meeting the standards
  originally envisaged. The detailed analysis revealed that the excellent results
  obtained earlier have been strictly accidental: the hydraulic efficiency
  happened to be stationary in the sample randomly selected!
  
  According to the above finding all attempts to identify the two parameters
  from two randomly chosen propulsion conditions are doomed to fail
  'by definition', due to the purposely simplified model.
  
  
  As has been observed earlier the thrust deduction axiom in accordance with
  the global approximation of the thrust deduction theorem is too crude
  to permit the identification of reasonable values of the energy wake fraction.
  Accordingly further attempts have been made to replace that axiom,
  though without success.
  
  But by the way it has been noticed that the value of the longitudinal hydrodynamic
  inertia crucially affects the momentum balance. With a more appropriate value
  than formerly assumed the final results are in nearly perfect agreement
  with those obtained in the traditional way based on results of propeller open water
  and hull towing tests.
  
  Further it has been observed that the inertia identified strongly depends on the
  maximum bandwidth of the filter applied to the raw data. Accordingly a procedure
  has been developed to extrapolate from quasi-steady conditions to the steady condition
  of interest.
  
  Due to problems with the pdf-writer the original printout of 20091020 has been replaced
  by the new printout of 20090626 without any changes in the evaluation.
  
  Last update and additions: 2009.06.26
  
  

Spreading the gospel

In a

• Letter to ITTC Committees concerned ,
  the Powering, Trials and Procedures Committees as well as the Quality
  Systems Group, the results obtained so far have been brought to the attention
  of the groups who may be most interested in the recent developments and
  in joining future developments of a corresponding scaling procedure.
  
  Subsequently
  
• A sign error
  has been detected in the re-evaluation, after the correction of which
  the 'rational' results are even closer to the traditional results than before.
  Consequently the scaling can be done as before, although the author feels
  that it needs to be reconsidered ab ovo as has been done with
  the performance and evaluation of model tests and of full scale sea trials.
  
  In order to spread the gospel a
  
• Presentation of the results,
  dedicated to the Centenary of VWS, Berlin 2003,
  has been prepared and updated after discussion
  at the Gdansk Ship Model Basin on July 05, 2002.
  
  On the occasion of the 23rd ITTC Venice 2002
  and the Centenary of VWS Berlin 2003
  an account of the developments and results
  of the rational theory over the last five years
  has been published.
  
  The following scheme provides a
  
• Survey of the various activities
  and their systematic interrelation.
  All the details are covered in the
  
• Summary of recent developments
  presented at the 20th Meeting of the Arbeitskreis Strömungsmaschinen
  at the Kvaerner Werft Rostock on November 08, 2002.
  
  The following .pdf file is a complete image
  of the introductory file of
  
• Mitteilungen der VWS, Heft 58,
  while the following .htm file
• VWS Mitteilung 58: live
  contains live links to the material included
  and all the background material.
  
  Some of the general aspects covered in the above collection
  of documents have been mentioned in
  
• Contributions to the discussions
  at the 23rd ITTC in Venice to be published in Volume III
  of the Proceedings.
  
  Since the lectures at MARIC the theory of ship hull-propeller interactions
  has been subject of lectures during the Winter-Semester 2004/5 at ISM/TUB
  and is subject of the paper
• 25 Jahre Rationale Theorie der Propulsion
  dedicated to Fritz Horn on his 125th birthday and originally to be presented
  
• 25 Jahre Rationale Theorie: presentation
  at the Summer Meeting of STG at Magdeburg in May 2005.
  Unfortunately this meeting had to be cancelled.
  
  During the lectures and the preparation of the paper the exposition of the
  
• Axiomatic system of wake and thrust deduction,
  underlying the evaluation of quasi-steady tests on model and full scale,
  has been elaborated in great detail.
  In addition the plots of the results of
• The quasisteady 'model' test
  have been improved by adding appropriate titles and labels.
  
  In the meantime the paper originally to be presented on occasion
  of the Summer Meering at Magdeburg has been presented on November 17, 2005,
  on occasion of the 100th Annual Meeting of STG at Berlin.
  Following the discussions the paper has been corrected and improved
  in a few places. 2006.03.28.
  
  The answers of the author to questions raised in the oral and written contributions
  are to be found in the
• Schlusswort des Verfassers
  dated 2006.03.31. For ready reference the
• Beitrag von Horst Nowacki
  is also provided.
  Further details may be found in
• fortgesetzte Diskussion
  with Prof. Nowacki.
  
  A closely related theme lecture on
• Propulsor Hydrodynamics: paper
  sumarised in an extended handout
  
• Propulsor Hydrodynamics: handout
  will be presented
  
• Propulsor Hydrodynamics: presentation
  at the International Conference on Marine Hydrodynamics, MAHY 2006,
  held January 05 to 07 at the Naval Science and Technological Laboratory
  at Visakhapatnam, India.
  
  The following four letters to Prof. Hans-Erhard Peters are concerned with
  optimum ship design and propulsion:
• Letter of 22.02.2006,
  
• Letter of 26.02.2006,
  
• Letter of 02.03.2006,
  
• Letter of 06.03.2006.
  
  Last update and additions: 2007.12.14