For an aircraft, rotorcraft or jet engine to obtain a type
design certification, it must be demonstrated that it can
sustain safe flight into known or inadvertent icing
conditions. The icing certification process involves CFD
(Computational Fluid Dynamics) analyses, wind and icing tunnel
testing (EFD: Experimental Fluid Dynamics), all considered
“simulation”, and final demonstration of compliance through
Flight Testing in Natural Icing (FFD: Flight Fluid Dynamics).
Modern 3D CFD-Icing methods such as FENSAP-ICE, working as a
direct extension of CFD-Aero technologies, have become an
indispensable, if not a primary tool, in the certification
process. They are rapidly replacing 2D and 2.5D methods
(airfoils don’t fly; aircraft do). They enable analyzing the
aircraft (fuselage, wing, engines, nacelles, cockpit windows,
sensors, probes, etc.) as a system and not as an assemblage of
isolated components. The judicial integration of CFD-EFD
simulation tools provides a cost-effective aid-to-design-and-
to-certification, when made part of a well-structured
compliance plan. CbA (Certification-by-Analysis) being a
current “hot” subject; this course puts it into real practice,
providing efficient tools and showing examples of capabilities
and limitations.
The course will show how modern 3D icing codes are
“predictive” as they are based on highly validated physical
models (Scientific VVV lecture). Just as one example,
critical ice shapes identification and corresponding
aerodynamic penalties based on 2D airfoil calculations may be
inaccurate if not altogether misleading as wings have breaks,
sweep, twist, spanwise flows, propeller and engine effects,
etc. that greatly affect/modify/delay stall and its
propagation.
The course will also show how Reduced Order Models can make
fully-3D calculations inexpensive (yielding 3D CFD with 10-20
million points + impingement + icing + performance in 1/100th
of a second, after the calculation of an appropriate number of
“snapshots”: this is even faster than 2D panel methods
calibrated codes!) and enable rapid identification of
aerodynamic and thermodynamic critical points in a structured
way and not a heuristic one.
The inclusion of icing requirements at the aerodynamic design
stage allows a more comprehensive exploration of the combined
aerodynamics/icing envelopes, optimized IPS design, and
focused/reduced wind tunnels, icing tunnels and flight tests.
The end result is a faster design, faster testing, faster and
more complete natural icing campaign, and a safer aircraft
that is easier to certificate and that remains problem free
during its lifecycle.
This course is structured to be of equal interest to
aerodynamicists, icing, environmental systems and flight
simulation engineers, regulators and Designated Engineering
Representatives. Detailed knowledge of CFD is not necessary.
The lectures cover the major aspects of in-flight icing
simulation, ice protection systems and handling quality
issues. The instructors bring an amalgam of knowledge, as
scientists who have developed codes in current use and
engineers with certification experience combining CFD-EFD and
FFD, along with cost-effective simulation methods widely used
internationally for certification of aircraft for flight into
known icing.
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