EN ISO 80000-11:2020

SLOVENSKI STANDARD
01-december-2020
Nadomešča:
SIST EN ISO 80000-11:2013
Veličine in enote - 11. del: Značilna števila (ISO 80000-11:2019)
Quantities and units - Part 11: Characteristic numbers (ISO 80000-11:2019)
Größen und Einheiten - Teil 11: Kenngrößen der Dimension Zahl (ISO 80000-11:2019)
Grandeurs et unités - Partie 11: Nombres caractéristiques (ISO 80000-11:2019)
Ta slovenski standard je istoveten z: EN ISO 80000-11:2020
ICS:
01.060 Veličine in enote Quantities and units
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 80000-11
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2020
EUROPÄISCHE NORM
ICS 01.060 Supersedes EN ISO 80000-11:2013
English Version
Quantities and units - Part 11: Characteristic numbers (ISO
80000-11:2019)
Grandeurs et unités - Partie 11: Nombres Größen und Einheiten - Teil 11: Kenngrößen der
caractéristiques (ISO 80000-11:2019) Dimension Zahl (ISO 80000-11:2019)
This European Standard was approved by CEN on 21 October 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 80000-11:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 80000-11:2019 has been prepared by Technical Committee ISO/TC 12 "Quantities and
units” of the International Organization for Standardization (ISO) and has been taken over as
which is held by CCMC.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by April 2021, and conflicting national standards shall be
withdrawn at the latest by April 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 80000-11:2013.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 80000-11:2019 has been approved by CEN as EN ISO 80000-11:2020 without any
modification.
INTERNATIONAL ISO
STANDARD 80000-11
Second edition
2019-10
Quantities and units —
Part 11:
Characteristic numbers
Grandeurs et unités —
Partie 11: Nombres caractéristiques
Reference number
ISO 80000-11:2019(E)
©
ISO 2019
ISO 80000-11:2019(E)
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
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below or ISO’s member body in the country of the requester.
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Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 80000-11:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Momentum transfer . 1
5 Transfer of heat .16
6 Transfer of matter in a binary mixture .24
7 Constants of matter.33
8 Magnetohydrodynamics.37
9 Miscellaneous .46
Bibliography .48
Alphabetical index .49
ISO 80000-11:2019(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see: www .iso
.org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 12, Quantities and units, in collaboration
with Technical Committee IEC/TC 25, Quantities and units.
This second edition cancels and replaces the first edition (ISO 80000-11:2008), which has been
technically revised.
The main changes compared to the previous edition are as follows:
— the table giving the quantities and units has been simplified;
— all items have been revised in terms of the layout of the definitions, and a worded definition has
been added to each item;
— the number of items has been increased from 25 to 108 (concerns all Clauses);
— item 11-9.2 (Landau-Ginzburg number) has been transferred in this document from
ISO 80000-12:2009 (revised as ISO 80000-12:2019).
A list of all parts in the ISO 80000 and IEC 80000 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2019 – All rights reserved

ISO 80000-11:2019(E)
Introduction
Characteristic numbers are physical quantities of unit one, although commonly and erroneously
called “dimensionless” quantities. They are used in the studies of natural and technical processes, and
(can) present information about the behaviour of the process, or reveal similarities between different
processes.
Characteristic numbers often are described as ratios of forces in equilibrium; in some cases, however,
they are ratios of energy or work, although noted as forces in the literature; sometimes they are the
ratio of characteristic times.
Characteristic numbers can be defined by the same equation but carry different names if they are
concerned with different kinds of processes.
Characteristic numbers can be expressed as products or fractions of other characteristic numbers if
these are valid for the same kind of process. So, the clauses in this document are arranged according to
some groups of processes.
As the amount of characteristic numbers is tremendous, and their use in technology and science is not
uniform, only a small amount of them is given in this document, where their inclusion depends on their
common use. Besides, a restriction is made on the kind of processes, which are given by the Clause
headings. Nevertheless, several characteristic numbers are found in different representations of the
same physical information, e.g. multiplied by a numerical factor, as the square, the square root, or the
inverse of another representation. Only one of these have been included, the other ones are declared as
deprecated or are mentioned in the remarks column.
INTERNATIONAL STANDARD ISO 80000-11:2019(E)
Quantities and units —
Part 11:
Characteristic numbers
1 Scope
This document gives names, symbols and definitions for characteristic numbers used in the description
of transport and transfer phenomena.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
Names, symbols and definitions for characteristic numbers are given in Clauses 4 to 9.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Momentum transfer
Table 1 gives the names, symbols and definitions of characteristic numbers used to characterize
processes in which momentum transfer plays a predominant role. The transfer of momentum
(ISO 80000-4) basically occurs during a collision of 2 bodies, and is governed by the law of momentum
conservation. Energy dissipation can occur. In a more generalized meaning momentum transfer occurs
during the interaction of 2 subsystems moving with velocity v relative to each other. Typically, one of
the subsystems is solid and possibly rigid,
...