SC 2004

GEWiTTS – GRID Enabled Wind Tunnel Test Service

SC 2004

Outline

• The GEWiTTS project

• Manchester University Transonic Wind Tunnel and PSP system

• GEWiTTS software architecture

• Firewalls

SC 2004

GEWiTTS

• Vision: Authenticated collaborative synergy between computational and experimental facilities

• GRID Enabled Wind Tunnel Test Service– Aim: Remote operation of wind tunnel data acquisition systems in a collaborative, virtual

organisational environment– PSP system used as a vehicle that supports high data rates, adaptability and remote processing of

results

• Addressing issues of:-– Remote collaborative control of experiments– Safety critical systems– Data confidentiality (https:)– Authentication– Firewalls

• Project partners– BAE Systems Advanced Technology Centre– BAE SYSTEMS (Warton) Air Systems– Manchester Uni – ARA

SC 2004

Manchester University TWT

-Suck-down tunnel-M = 0.3-0.8-1 minute runtime-15 minutes duty cycle-Hazardous environment

SC 2004

Beam Steering Mirrors

LASER

Polymer and dye

Substrate

•Organic dye dissolved in gas permeable polymer absorbs green photons

•Re-radiates at longer wavelength

•Oxygen molecules in the polymer can quench this process

•Relationship between emitted photons and air pressure

•Real time data msec & sec timescales•Configurable on-the-fly

•Equivalent to computational steering•High data rates•Class IV laser

SC 2004

Chemistry Stuff

Metalloporphyrins

Visible wavelength absorption bands - 532nm coincides with freq doubled Nd:Yag

Useful (easily measurable) phosphorescence- 650nm

Platinum meso-Tetra-(pentafluorophenyl) porphine, Pt(TfPP).

Siloxane polymer - rubbery coating, 20-30m thick, high gas permeability

Permeability = ƒ(T)

SC 2004

Decay Lifetime Measurement System

Return signal is close to an exponential

independent of initial excitationno paint thickness/uniformity effectsno sensitivity to surface curvaturedye concentration or uniformity has little effectambient light levels are irrelevant

Reference image/measurement not required

Application to high data rates

Sufficient data for simultaneous two variable extraction (P+T)

SC 2004

ARA Wind Tunnel Tests

• Large Transonic Wind

tunnel In UK

• Fully automatic operation

• Data on-line within 5-ish

seconds

• Edge detection routines

used for model location

SC 2004

Approximate area covered byzoomed scan below

Bracket

Upper Surface Tailplane at M=0.8, 10o

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Client 1

Client n

Wind tunnel 1

Wind tunnel n

GEWiTTS scenario

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GEWiTTS software

• Servers– PSP system server

• Can support multiple clients– Tunnel Control System server– Interlocks

• Client– Can support multiple servers– Performs processing and display of results

• Management application– Health & Safety– Security– Validation– Collaborative working process

Portal – real time

SC 2004

List of experimental sessions being run at

the facility

List of clients taking part in each session and the controller of

the experiment

List of PSP servers in each session

Interface with tunnel control system

Video output to clients

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List of active sessions

Status of client

Client interface

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Lessons learned(1)

• Collaborative working

– Overall control of experiment rests with facility operator (H&S concerns)

– Partial control can be delegated– SessionManager (or portal) is tightly bound to facility

– Very similar to the dynamics of a meeting– Designation of experiment leaders and viewers is critical– Access is granted and validated on a session-by-session basis

– A separate dialogue application (a chatter example) is vital

– Good visual feedback on application status is essential in real time applications

SC 2004

Lessons learned(2)

• User or client validation

– Essential– User ID must propagate through audit trail

• Certificates allow single sign-on use-anywhere• Are usually not time-bound

– Solution is to generate unique ID at use time• Fingerprint ID allows access to .exe created for that user only• Timestamps

Fingerprint ID

Browser

Compile client.exe

Database

HTTPS

SC 2004

Firewalls and other irritations

• BAE Systems and its partners operate strict firewall policies

– Traversing multiple firewalls is a difficult but unavoidable task– Connections can only be initiated on http or https– Security and user validation is essential

• Export licenses

– Remote execution of code and data traversing international boundaries create specific problems

• ISO9001/2

– Audit trails – confidence that repeat computations give identical results

SC 2004

Summary

• PSP system and a wind tunnel can be operated remotely in a real-time multi-user collaborative working scenario for integration within the CFD driven design process

• Dynamics of a collaborative working environment mimic those of a traditional meeting, and software has been developed to reflect this