BS EN ISO 80000-11:2020

What is ISO 80000‑11 about? 

ISO 80000-11 is the 11th part of a series of documents on quantities and units. ISO 80000‑11 gives names, symbols and definitions for characteristic numbers used in the description of transport and transfer phenomena. 

Who is ISO 80000‑11 for? 

ISO 80000‑11 on quantities and units - characteristic numbers is relevant to:  

• Fluid dynamics 
• Professors 

Why should you use ISO 80000‑11?  

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. 

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 ISO 80000‑11, where their inclusion depends on their common use. 

With the use of ISO 80000‑11, you can present information about the behaviour of processes and reveal similarities between different processes. This can help you to avoid redundancies and make your organization more efficient. 

What’s changed since the last update?  

BS EN ISO 80000‑11:2020 supersedes BS EN ISO 80000‑11:2013, which is withdrawn. BS EN ISO 80000‑11:2020 includes some technical changes with respect to BS EN ISO 80000‑11:2013. These are: 

• 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)