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Document Review Criteria for the “Future of Ground Testing” Working Group
Draft by Dunn, 4/2/15
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I.
The focus of this report is ground testing. We will include information on flight testing as it is
included in our reference material. We may need an additional effort to beef up the FT info.
This is organized in a gap analysis structure: future vision, current state, opportunities and
challenges (including “grand challenges”)
The first part of this document lists the criteria for review. Please scan these prior to reviewing the
paper. This is intended to show the intent of the type of info to be documented.
The second part of this document lists topic areas. Please add your comments to each, as applicable.
Write as much or as little as you want; we will be combining inputs for each paper. We really want
to capture the author’s intent, add anything additional that you feel is important that is not
captured by these topic areas.
Vision for Experimental Fluid Dynamics – Ground (and Flight, as mentioned) Testing
a. Expected/Projected Needs
i. Military
1. Fixed wing
2. Rotorcraft
3. UAV/Missile
4. Other
ii. Commercial
1. Fixed wing
2. Rotorcraft
iii. General Aviation
iv. Space transportation delivery and return systems
v. Fundamental research
b. Capabilities
i. Mission-related performance requirements
ii. Degree/Mix of Work Done by EFD or CFD
iii. Ownership/Stewards and Cost Models
iv. Operational Models
c. Integration
i. Risk Management during Development
1. EFD/CFD tool selection
2. EFD Quality versus Cost
3. CFD Quality versus Cost
4. Tool Interfacing
5. “Good Enough” for
ii. Efficient, Cost-effective
d. Grand Challenge Problems
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II. Current State of EFD
a. Performance/Benchmark
i. Fundamental Research, Elemental and System
ii. Design
1. Conceptual Design
2. Preliminary/Detailed Design
3. Product Validation and Certification
b. Capabilities
i. Mission area(s) Performance Availability
1. Physical condition
a. Good or better condition
b. Past design life
c. Issues and at risk
2. Capability sustainment efficacy (maintenance, investments, skill
management, operations and maintenance processes, budgets and business
processes)
3. Improvement and modernization alignment with future market needs
4. Customer focus (for all customers
ii. Staffing and Knowledge Management
c. Integration
i. Computational methods
1. Maturation of computational processes
2. How GT techniques and processes must evolve to support integration
ii. Support to flight testing
iii. Measurement and instrumentation technologies maturation, including teaming to
define needs to measurement developers and producers (again, integrated with CFD
and flight test)
iv. Government and industry development, proprietary versus open source
III. EFD/Ground Testing Technology Gaps and Impediments
a. [Note: This is likely a work product from assessing the first two sections. Included to capture
anything already identified in the references.]
IV. Technology Development Plan
a. [Address the gaps]
Additional Considerations
There will be additional info that doesn’t fit into the above categories and we still need to capture that
and then figure out how it fits into our paper. The following is a start at some of this potential info.
V. Internal and External Environments
a. Interdependencies within the RDT&E process and risks associated with potential loss of GT
capabilities
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b.
b.
c.
d.
e.
i. Example: Accepting higher risk by not understanding product performance such that
defects appear late in the RDT&E life cycle -- very costly to fix late
Facility owner needs and issues
i. Mission requirements and priorities
ii. Condition of facilities
iii. Capability sustainment efficacy (maintenance, investments, skill management,
operations and maintenance processes, budgets and business processes
iv. Improvement and modernization alignment with future market needs
v. Customer focus/service
Producer risk management needs and issues
i. [Definition note: risk management is the definition of hazards, the probability a
hazard will happen, the potential severity/impact when it happens, an initial risk
level assessment, development and application of specific mitigators to a high risk
hazard, and a reassessment of risk with mitigators in place. Process continues until
hazards are well understood and risk levels have been mitigated down to acceptable
levels.]
ii. Always a trade to define GT and CFD requirements to drive risk down for specific
hazards
iii. CFD mostly requires validation (typically via GT or FT)
iv. GT and CFD also used to define some hazards
Economic impacts
i. United States, EU and Great Britain, Japan
ii. Breakouts based on GDP, jobs, net imports/exports
iii. Technology spin-offs, estimate of additional positive impact on GDP
Education impact (STEM support,
Environmental headwinds and support (in addition to cited above, add geopolitical
considerations, overall economic indicators, national and international politics
(regulations/laws, taxation, market support or not, more)
VI. Needs and Capabilities
a. Computational methods
i. Code validation
ii. Interactive development
b. Flight testing investigations
c. In service product anomaly investigations
d. Measurement and instrumentation technologies development
e. Role in RDT&E process, at each stage; percent and relative importance of knowledge
gained at each stage; degree of risk identified and managed at each stage for different
kinds of systems at different levels of maturation
f. Market environment, growing, stagnant/mature, declining, cyclical
i. Low/subsonic speed
ii. Transonic speed
iii. Supersonic speed
iv. Hypersonic speed
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Document Review Form for Capturing Information from Selected GT References
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References and reviewers were identified at the SciTech meeting. Each reviewer should use this
form – hand or type written – to capture info as a document is reviewed.
Send completed reviews to Steve Dunn at steven.c.dunn@nasa.gov.
Reviewer: __Eric Schuch__________________________
Reference Document Title: __AIAA-2010-142-709 Wind Tunnel Future_________
Date of Review: __5/31/2015______________
Please fill in each topic area, as applicable (add space as needed):
I.
Vision for Experimental Fluid Dynamics – Ground (and Flight, as mentioned) Testing
a. List/describe future technologies/configurations in terms of Expected/Projected Needs
This paper outlines several areas of emerging technology that will require improve T&E
assets:
 “High-speed testing for transonic transports to hypersonic vehicles: Facilities to test
transports, high-altitude ISR, and time-critical-to-target platforms are reaching
critical mass; and they are in need of major upgrades or maintenance to continue
operation. In addition, to answer the government’s challenge of advancing our
technology to reduce energy consumption, reduce noise impact, and improve
vehicle performance, these major tunnel facilities will need to support nontraditional concept entries requiring unique or innovative test methodology.
 Low Reynolds number (Rn) micro UAV flight (ultra low turbulence) simulation:
Adequate tunnel facilities are still available to address normal low-speed testing.
The Air Force Research Laboratory’s “challenge growth initiative”11 may be the
venue to address wind tunnel test needs for nano and micro UAVs.
 Unsteady aerodynamic testing for flapping wing. Urban flow, large-turbulence
testing for micro vehicles and hybrid airships.
 Stratospheric test capability ranging in Mach numbers from 0.5 to 2.5, Rn/ft up to 5
million, dynamic pressures up to 1500 psf and simulating altitudes up to 80,000 ft
are required.
 Low Rn, ultra-low-turbulence flow for ISR platform testing.
 High Rn low-turbulence flow for high-speed platforms.”
b. What capabilities will be needed and how will they need to work and be managed?
This paper describes what the ideal future would look like:
“The most ideal future scenario will include highly integrated computational and physical
simulation capable of rapid evaluation of concepts and configurations. Robust and reliable
CFD modeling simulation will be used to evaluate and narrow the design options to a chosen
few. Rapid wind tunnel model design and fabrication would begin taking advantage of lightweight, easily workable, and high-strength materials to manufacture modularized model
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parts for testing. Wind tunnels would be readily available with capabilities spanning a large
speed range and flow visualization at any speed, efficient data gathering process (hardware
and software), automation that reduces model changes, and adaptable to various types of
testing, i.e., aero, propulsion, loads, and noise. Entries in the tunnel will be shorter and more
rapid, providing focused physical validation of analytic estimates and, where appropriate,
volumes of data required for extensive control law and flight envelope expansion.”
It goes on to recommend future capabilities:
 “Multi-mission capability. Any new test facility must be capable of a broad range of
test types and speed ranges. Speeds from M=0 to M=5.0, altitude simulations up to
80,000 ft (stratospheric testing), Reynolds numbers up to 5 million/ft should be
capability goals.
 Moderate Test sections size. Approximate 60 to 100 sq. ft. test section size is a
reasonable compromise between high-cost large-volume test section sizes for large
models and efficient, low-operational-cost smaller facilities. This nominal test
section size facilitates models of reasonable size to obtain reliable data and without
flow issues such as blockage, flow breakdown, and shock reflections.
 Advanced data mining capability. Real-time quantitative and visualization data of
on- and off-body flow fields will be required to integrate and validate computational
simulations.
 Excellent test section optical access for application of developing on- and off-body
flow visualization and measurements. Future data mining requirements (above) will
drive significant optical access requirements.
 Ease of access and installation. With the anticipation that future windows will
require rapid access, new capabilities must have extremely rapid access. The ability
to install and test a model within a single operational shift is essential.
 Highly automated testing. Efficient and highly productive operations will drive crew
sizes down in favor of automation. Tunnel and model automation capability are a
must for any future capability.
 Highly connected facility. Full remote access, including data streaming, audio and
video feeds (to facilitate virtual presence), will enable test teams to be spread
across the nation without the requirement to physically attend testing. Fully
integrated computational access to existing design simulation or test databases is
essential.
 Ability to create model configurations on-site. Rapid model creation capability (as
discussed in previous sections) will become essential to a rapid test mindset.
 Energy efficiency. Any new facility must be extremely energy efficient. Evaluation of
non-traditional designs such as oval circuits, multi-cycle test environments,
extremely low-friction circuit design, and variable test section sizes should be
important considerations.
 Expert staff. Test success is more often influenced by the expertise and behavior of
the staff than by equipment or underlying infrastructure. To enable rapid, efficient,
and successful testing, a well rounded staff of experts (in both facility operation and
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aircraft development) is needed. The ability to perform testing without extensive
customer presence absolutely revolves around a facility having expertise and
efficient processes.”
c. Integration of CFD and Ground/Flight Testing (includes risk management during research
and product development)
This paper outlies 4 main points needed to achieve the ideal scenario
“Achieving this ideal scenario requires significant progress across many fronts:
 Improvements in speed and accuracy of computational simulation
 Highly integrated simulation and wind tunnel testing
 Rapid development of wind tunnel model hardware
 Wind tunnel facilities capable of rapid evaluation of on- and of-body flow physics for
identified configurations for a broad range of test types and speed ranges.”
d. Grand Challenge Problems
II. Current State of EFD
a. Performance/Benchmark – types of capabilities/test techniques, where it works best, best
practices, how do we know
b. Capabilities
i. Mission area(s) Performance Availability (strengths and weaknesses associated with
condition, investments, capability sustainment, reliability, customer
focus/satisfaction)
One of the weaknesses of EFD mentioned in the paper is the design and fabrication
of the model. Different speed ranges typically require different wind tunnels and
thus separate model and test entries. The paper identifies the need for continued
advancement in rapid prototyping strength, size, and accuracy.
ii. Staffing and knowledge management
c. Integration
i. Computational methods
1. Maturation of computational processes
2. How GT techniques and processes must evolve to support integration
“Simply replacing or supplementing one tool with another does not
optimize design efficiency. Use of approaches like Modern Design of
Experiments (MDOE) is required to truly increase the effectiveness of the
process. Integration also requires careful alignment of processes used. As an
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example, it is not unusual to discover (usually afterwards) that CFD models
do not match the wind tunnel model, thus throwing into question the
validity of computational solutions. Test conditions in the tunnel are often
run without regards to the computational simulations performed
beforehand. These seemingly simple process issues often detract from the
entire process efficiency.”
ii. Support to flight testing
iii. Measurement and instrumentation technologies maturation, including teaming to
define needs to measurement developers and producers (again, integrated with CFD
and flight test)
iv. Government and industry development, proprietary versus open source
III. EFD/Ground Testing Technology Gaps and Impediments
a. [Note: This is likely a work product from assessing the first two sections. Included to capture
anything already identified in the references.]
IV. Technology Development Plan
a. [Address the gaps – include anything already identified in the references.]
Additional Considerations
There will be additional info that doesn’t fit into the above categories and we still need to capture that
and then figure out how it fits into our paper. The following is a start at some of this potential info.
V. Internal and External Environments
VII. Needs and Capabilities (not covered above)
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