Expertise de Frank LU, professeur en aérodynamique à l'Université de Texas, Arlington

 

    Voici notre conversation avec Frank LU, professeur et directeur du centre de recherche en aérodynamique de l'Université de Texas à Arlington aux Etats-Unis.

    Voici la première lettre que nous avons envoyé au professeur Lu, sans véritable espoir de réponse...

    Sir,

    Lucas D, Guillaume de N. and myself, Augustin M. are currently second year senior high school students.

In the horizon of the Baccalauréat -French high school final exam- each student must conduct a science project. The project will be marked for senior high school final exam.

Thus we turn to you for your expertise and advices.

 

  Our project is the following one : we imagined an ideal airliner by bringing together aerodynamic innovations inspired by nature (please see attached files for details).

We have retained three main ideas :

  • Winglets inspired by birds shall permit fuel saving since it reduces greatly the trail.

  • An artificial « shark skin » coating covering 40% to 70% of the aircraft might, according to our readings, allow a saving of about 1 to 2% of fuel.

  • Finally, leading edges inspired by whales' fins design may also reduce the trail.

The airliner model we imagined and named ECHO, brings together those three innovations. We do also care for passengers comfort; we do believe that our ideal plane must be supersonic like the legendary Concorde.

 

  We are looking forward your advices and your input on our project. We thus want to ask you some questions :

  • Could our plane fly ?

  • Is a leading edge inspired by whales' fins feasible ?

  • What comment do you have on our project ?

  • Which are nature inspired innovations applicable to the aerodynamic field ?

  • How to pass from the analysis of aerodynamic phenomenons to more concrete applications ?

  • Do you have the knowledge of biomimicry applied to aerodynamic which is used on aircraft ?

 

I look forward to your response and your thoughtful advices.

Respectfully yours.

 

    Mais contre toute attente, Le professeur de l'université d'Arlington nous a répondu ! Voici sa réponse :

Dear team,

 

Your design is extremely intriguing and I urge you to study it further.  Biomimicry is a hot topic but bear in mind that you are extrapolating to flight regimes beyond what Mother Nature has intended.  Let me answer below directly.  With best wishes,

 

Frank Lu

 

  • Could our plane fly ? Yes, I cannot see any reason not too.

  • Is a leading edge inspired by whales' fins feasible ? I am not clear what is this whales' fin so I cannot comment.

  • What comment do you have on our project ? The practical feasibility of shark skin is the showstopper.  How to make and how to maintain.

  • Which are nature inspired innovations applicable to the aerodynamic field ? This is too general.  There are many books on this subject.

  • How to pass from the analysis of aerodynamic phenomenons to more concrete applications ? This is where you have to go to university.

  • Do you have the knowledge of biomimicry applied to aerodynamic which is used on aircraft ? There is interest especially for small unmanned vehicles for morphing wings.

A general comment. Since you are thinking of supersonic flight, bear in mind the noise issue.  There are various new ideas on designing to minimize sonic boom.  Please check NASA and AIAA websites.

You and your team are definitely asking the tough questions.  I'm not sure how's your library access but journals you may want to read are: Progress in Aerospace Sciences, Aerospace Science and Technology, AIAA Journal and Journal of Aircraft.  There are a few textbooks on the matter.  But technology is moving rapidly.  Also, for applications outside the realm of birds and bees, you have to be realistic.  Our biggest challenges at those speeds are sound and drag, where the latter is dominated by shocks.  Shock waves over external surfaces cause drag (known as wave drag).  Shock waves in internal passages such as inlets also create drag but additionally can result in distortion and poor flow quality into the rest of the engine.

Enjoy your studies and best of luck.

Frank Lu

 

Nous tenons donc à remercier Mr Franck Lu de ses précieux commentaires sur nos travaux.

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