Thoughts of a poor old sod

Flummery & Flannery

Application Challenge AC7-01

Overview of Tests

Provide an overview of the scope of the tests and the experimental approach used. This should cover the main aspects of the experimental set up and the measurement techniques used (LDV, hot wire, pressure tappings etc).

If a scaled model was used, due consideration should be given to model scaling issues. Any model simplifications/idealisations of the AC geometry should also be described (e.g. 2D instead of 3D, omission of detailed features, simplification of complex features, i.e. porous media, use of roughness elements). If important details of the geometry representation are uncertain then the impact of these uncertainties on the DOAPs should be discussed, including possible ways for managing their effect.

Sampling/averaging times, and their effect on quantities measured and on DOAPs in particular, should also be discussed.

Identify all experimental tests for which data is available. In order to minimise the number of test descriptions, it is suggested that, as far as possible, experimental data from various runs or experimental conditions be grouped together under a single test case, if variations to experimental setup can be clearly defined in terms of:

the governing non-dimensional parameters (GNDPs defined above in 1.5), or

problem definition parameters (PDPs), such as wind direction, angle of attack, aspect ratio, source rate etc.

It is left to the discretion of each author to decide the most appropriate way for structuring and summarising the test case results, within the broad framework suggested above.

A summary table for all tests should be included as shown below in Table EXP-A. The variables measured in each test should also be clearly identified, (e.g. UVW, k, concentration, etc). A distinction should be drawn between detailed local data (e.g. p(x,y,z)) and data relating to DOAPs which are likely to be global/summary parameters (e.g. coefficient of lift, CL).

All available detailed data should be stored in separate electronic datafiles (according to guidelines set out by the Knowledge Base team at the University of Surrey). These should be summarised as shown below in Table EXP-B, with links to each of the datafiles.

**Table EXP-A Summary description of all test cases**
Name	GNDPs		PDPs (problem definition parameters)			MPs (measured parameters)
	Re	Fr	Wind direction	Source rate (kg/s)	Release density(kg/m³)	Detailed data	DOAPs
Exp 1 (dense gas dispersion)	$10^{5}-10^{6}$	$0.2-10$	0, 30, 45, 90, 180	$1-3$	$1.22-3.00$	$C,\ U$	${\ C/C_{0}}$
	Re		Wind direction	Building geometry		Detailed data	DOAPs
Exp 2 (passive gas releases)	$10^{5}-10^{6}$		0, 30, 45	A, B, C, D		$C,\ U,\ V,\ W,\ k$	${\ C/C_{0}}$

**Table EXP-B Summary description of all measured parameters and** **available datafiles**
	MP1 $U,\ V,\ W\ (ms^{-1})$	MP2 $k\ (m^{2}s^{-2})$	MP3 $C\ (kg/m^{3})$	DOAPs, or other miscellaneous data
EXP 1	✔✘✘ exp11.dat	✘	✔ exp13.dat	—
EXP 2	✔✔✔ exp21.dat	✔ exp22.dat	✔ exp23.dat	exp24.dat

TEST CASE EXP1

Description of Experiment

Quantify the parameters that define this particular set of experiments (GNDPs and PDPs). Describe which parameters were measured (MPs), where in space and time (state units in SI). Conventions for presenting data in each of the datafiles should be simple, and clearly stated.

Boundary Data

Specify in detail the conditions pertaining at all boundaries on all dependent variables (data need not be quantified here if included as a dataset). The boundaries should include inflows, symmetry surfaces, walls, far-fields, free surfaces and outflows. If the walls are rough, roughness heights should be specified. Are the turbulent stresses and length scale measured at inflows? If not give advice on how these should be set up. If any boundary data is uncertain then discuss the sensitivity of DOAPs to this uncertainty. Is there any reasonable way of managing this uncertainty if the sensitivity is appreciable?

Measurement Errors

A realistic estimation of the accuracy of the data (crucially important for the DOAPs) employing one or more of the following:

Appraisal of the accuracy of the measured quantities arising from the given instrument/technique (error bars are desirable)

Repeated or reference measurements, and calibration checks.

Demonstration of consistency in the measurement of different quantities

Checks on the global conservation of physically conserved quantities.

Measured Data

List all data measured, with links to all data files. Describe the data storage format used, and specify measurement positions (preferably on a diagram of the flow domain).

For example:

EXP1 Dense gas release measurements: mean and RMS measurements of each of the three wind components (U along-wind, V lateral and W vertical), at 4 heights and 7 locations downstream of the building. Ground level concentrations at 7 locations downstream of the building.

exp11.dat ASCII file; headers: Re, Fr, wind direction, source rate, release density;

columns: