ISO 8625-2:2018

INTERNATIONAL ISO
STANDARD 8625-2
Second edition
2018-03
Aerospace — Fluid systems —
Vocabulary —
Part 2:
General terms and definitions
relating to flow
Aéronautique et espace — Systèmes de fluides — Vocabulaire —
Partie 2: Termes généraux et définitions relatifs à l'écoulement
Reference number
©
ISO 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
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
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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
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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
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URL: www .iso .org/ iso/ foreword .html.
This document was prepared by ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 10, Aerospace
fluid systems and components.
This second edition cancels and replaces the first edition (ISO 8625-2:1991), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— Clause 2 has been added, moving the “Terms and definitions” to Clause 3;
— Clause 3 has been technically revised and editorially reworked;
— the example for a definition at the beginning of Clause 3 has been deleted;
— the definitions in Clause 3 have been renumbered accordingly;
— the definitions for “laminar flow” and “turbulent flow” have been added as a sub-entry to the
definition of “flow”;
— “flow factor” and “flow coefficient” have been combined under sub clause 3.4;
— “quiescent flow” and “seal leakage/seepage” have been moved as sub-entries to 3.7 (“leakage”);
— the definition for “Reynolds number” has been added to Clause 3 as sub-entry 3.10;
— the definition for “weepage” has been deleted; and
— the “Alphabetical Index” has been deleted.
A list of all parts in the ISO 8625 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 8625-2:2018(E)
Aerospace — Fluid systems — Vocabulary —
Part 2:
Gene
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