Units of Measure for use in Math-ML datasets

[Brian, Geoff]

Title: Re: Use of Math-ML with DAVEfunc Version 1.7b1

Hi all,

 

I noticed in the DAVE-ML reference that the issue of units-of-measure notation is still to be finalised.

I have been looking at this for our flight dynamic / simulation modelling here in DSTO, and have found that a number of the

proposed standards have conflicting information for units of measure, both between standards and within individual standards.

As a result, I have prepared a list of units of measure for use with aircraft modelling here in DSTO (see attached). A difference

I have adopted from general conventions is the use of negative powers to represent divisor units irrespective of whether the

unit of measure is metric or imperial (eg. ft s-1 instead of ft/s). I have found this is simpler when defining something like

ft s-2 instead of ft/s/s or ft/s2.

 

 

I thought that this might be useful as a starting point for defining a units-of-measure notation for Dave-ML and welcome any comments.

 

The references I have used for compiling the list were:

    "Standards for the Exchange of Simulation Modeling Data", Preliminary Draft, 9 June 1997, AIAA Modeling and Simulation Technical Committee.

    "SI Units Dimensional Analysis &, Chapter 8 Figure -- Conversion Tables", McMahonlines, MathTech Reference Series.

    http://www.unc.edu/~rowlett/units/index.html

 

hope you are having an enjoyable lead up to the end of the year.

Regards

 

Mr Geoff Brian
Aircraft Flight Dynamics and Performance Engineer.
Air Vehicles Division,
Defence Science and Technology Organisation.

Ph. (03) 9626 7318,
Fax (03) 9626 7085.
e-mail: [EMAIL PROTECTED]

Title: Flight Systems Units of Measure Guidelines

Flight Systems Units of Measure Guidelines.

$Revision: 1.1$
$Date: 2004/10/26$
Written by: Geoff Brian ([EMAIL PROTECTED])

Table of Contents

1. Introduction
2. Comments
3. Units of Measure Abbreviations
4. References

Introduction

This document, although not exhaustive, lists abbreviations for units of measure common in the Aircraft Modelling and Simulation community.

Aircraft flight simulations and models compute the behaviour of the aircraft subject to stimuli such as flight control system inputs and environments influences. They also rely on a representation of the physical properties of the aircraft such as its aerodynamics, propulsion system and mass properties. Data detailing the inputs and outputs from simulations, as well as the physical properties of the aircraft, have different units of measure, and also may be mixed between Système Interantionale (SI) units and Imperial units. This guideline presents the units of measure for data utilised by aircraft simulations and models developed by Flight Systems, Air Vehicles Division, DSTO. The Flight Systems Units of Measure Guideline is based on the AIAA Modeling and Simulation Technical Committee "Standards for the Exchange of Simulation Modeling Data -- Preliminary Draft", [1].  

Comments

1. Data may have a base unit of measure, as shown in following table, or may be a combination of units; for example, metre: m or acceleration: m s^-2.
2. The prefix abbreviations are applied to the base unit of measure abbreviation, and scale the data using values in the comment box; for example, millimetre: mm = 10^-3 m
3. For data that have a combined unit of measure, they will be defined using base units elements separated by a blank space; for example, fuel flow rate:  l s^-1
4. Divisor units of measure are represented by the unit abbreviation raised to the equivalent negative power; for example, feet per second is represented as ft s^-1 
5. Velocity is generally represented using a combined unit of measure; for example, m s^-1. However, the knot is a recognised measure in the aviation community and thus included.

Units of Measure Abbreviations

SI - Système Interantionale

Measure	Abbreviation	Comments
General
non-dimensional	ND	Used if non-dimensional parameter
Prefix 2
tera	T	1012 * parameter
giga	G	109 * parameter
mega	M	106 * parameter
kilo	k	103 * parameter
deci	d	10-1 * parameter
centi	c	10-2 * parameter
milli	m	10-3 * parameter
Time
Solar year	yr
Solar day	day
hour	h
minute	min
second	s	SI Standard
Length
metres	m	SI Standard
inch	in
feet	ft
yard	yd
nautical mile	nmi
statute mile	smi
Velocity 5
knot	kn	nmi h-1
Volume
litre	l	10-3 m3
US gallon	USgal
UK gallon	UKgal	Imperial Gallon
Mass
kilogram	kg	SI Standard -- 103g
gram	g
tonne	tonne
slug	slug
short ton	USton	US Ton
long ton	UKton	UK Ton
Force
Newton	N	SI Standard
Pound Force	lbf
Pressure
Pascal	Pa	N m-2
millimetres Mercury	mmHg
Pounds per square foot	lbf ft-2	lbf ft-2
Pounds per square inch	lbf in-2	lbf in-2
inches Mercury	inHg
Atmosphere	atm
Temperature
degrees Kelvin	K	SI Standard
degrees Centigrade	C
degrees Farenheight	F
degrees Rankin	R
Viscosity
Poise	Ps	Dynamic viscosity
Stokes	St	Kinematic viscosity
Plane Angle
degree	deg
radian	rad
revolution	rev
Power, Energy
Watt	W	SI Standard
horsepower	hp	550 ft lbf s-1
joule	jou	SI Standard
British thermal unit	btu
calorie	cal
erg	erg
Electrical, Magnetic
volt direct current	Vdc
volt alternating current	Vac
ampere	A	SI Standard
omh, resistance	ohm	SI Standard
cycle	cyc
henry	hy
farad	fd
Telsa	T	field strength

References

1. "Standards for the Exchange of Simulation Modeling Data", Preliminary Draft, 9 June 1997, AIAA Modeling and Simulation Technical Committee.
2. "SI Units Dimensional Analysis &, Chapter 8 Figure -- Conversion Tables", McMahonlines, MathTech Reference Series.
3. http://www.unc.edu/~rowlett/units/index.html

    

---