I am a Senior Lecturer in Digital Engineering of Structures (and former Royal Academy of Engineering Research Fellow) based at the Bristol Composites Institute of the University of Bristol. My research investigates novel forms of lightweight structural design in multiple engineering sectors using composite materials and multi-functionality.
Here my focus is particularly on active matter, i.e. developing materials and structures that react and optimally adapt to changing environmental conditions. At a system level, this approach is often known as morphing, such as a bird’s ability to morph its wings on the fly. In essence, active matter implies a paradigm shift in engineering design—from avoiding nonlinear phenomena to actively embracing them—leading to unique challenges in how to best model, test, and validate such behaviour in industrial practice.
If you want to learn more about this research, then check out the dedicated blog post that I have written on this topic.
You can find my contact details and further details below. To get in touch, please leave a comment or send an email, and I will get back to you ASAP.
Rainer Groh, MEng PhD CEng MRAeS
Senior Lecturer in Digital Engineering of Structures
Bristol Composites Institute (BCI)
Department of Aerospace Engineering, University of Bristol
Queen’s Building, University Walk, Bristol, BS8 1TR, UK
email: contact@aerospaceengineeringblog.com
social media: LinkedIn
PhD Thesis
RMJ Groh (2015). Non-classical effects in straight-fi bre and tow-steered composite beams and plates. University of Bristol. Bristol, UK.
Teaching
Aerospace Vehicle Design and Systems Integration (2022 – ): Group advisor on a concept study of a new fixed-wing aircraft, Department of Aerospace Engineering, University of Bristol.
Nonlinear Structures and Structural Stability (2019 – ): Lectures on Nonlinear Continuum Mechanics and Nonlinear Finite Elements, Department of Aerospace Engineering, University of Bristol.
Research Project 3 (2019 – ): 3rd year undergraduate research project supervisor, Department of Aerospace Engineering, University of Bristol.
Advanced Materials & Structures 3 (2015 – 2019): Lectures on Bending and Buckling of Plates, Department of Aerospace Engineering, University of Bristol.
Publications and Conference Proceedings
See Google Scholar and ResearchGate
Awards
- Nominated for Blavatnik Awards for Young Scientists in the UK, 2022.
- Philip Leverhulme Prize, 2019.
- Royal Academy of Engineering Research Fellow, 2018-2023.
- Honourable Mention Award at the ACM Conference on Human Factors in Computing Systems, 2018.
- European Commission CleanSky2 Academy PhD Awards, 2018.
- Collier Research HyperSizer/AIAA Structures Best Paper Award, AIAA SciTech, 2015.
- Ian Marshall’s Award for Best Student Paper, ICCS17, 2013.
49 Responses to Contact
Leave a Reply Cancel reply
This site uses Akismet to reduce spam. Learn how your comment data is processed.
Hello, Rainer! I’m a pilot in the U.S., flying a Boeing 737. I’ve always been interested in the hows and whys of aircraft design (not all pilots are so interested, though). I’ve always wondered: the 737 cockpit is rather noisy in flight, especially above 250 knots indicated airspeed. Why are some nose designs so different, and how do they affect aerodynamic efficiency and cockpit noise? For instance, the de Havilland Comet used a completely faired nose. But, the 707/727/737 use a stepped nose design, with considerable sharp corners and angles. The 757 nose is much more streamlined (at least it looks that way), and I’ve wondered if it results in less drag than the 707/727/737 nose. Also, all the new-generation aircraft (Boeing 787, Bombarier C-Series, Embraer 170/190) use a completely faired nose section, like the Comet. Could you do an article discussing these traits, and particularly, addressing if the 737 nose section is particularly “draggy?” With the 737MAX on the horizon, I’d like to know if Boeing missed an opportunity to do away with the old 1950’s-era nose section. Thanks! I enjoy your blog.
Hi Steve, as you pointed out the shape of the nose is heavily influenced by attempts to reduce drag and thereby maximise aerodynamic performance. The optimum shape of the nose is often determined by the desired flight velocity and therefore the type of flow that passes over the nose section. For commercial subsonic flight pressure-drag due to boundary layer separation is largely non-existent, so most of the drag is a result of skin-friction drag. The shear stresses that cause skin friction are also directly responsible for the noise levels within the cockpit. Skin-friction drag depends on the wetted area and type of flow (laminar or turbulent). For minimum friction and noise you ideally want laminar flow over the nose, which is really difficult to maintain due irregularities in the surface (bugs, scratches, dents) and the presence of any discontinuities in the shape that may trip the boundary layer. So for your 737 you ideally want a short, blunt and smooth elliptical shape. However, the shape of the nose is of course also influenced by packaging constraints for electronic and hydraulic actuating systems etc. and effectively channeling the flow to the rear parts of the aircraft where most of the lift is generated. So as is typically the case, some sort compromise has to be struck in order to maximise the overall performance. I am by no means an expert on the detail design of noses though, so I will do some research and then write an article about the findings. Cheers for reading the blog!
Regards,
Rainer
The 737 nose was copied from the 707, and both use large, flat window panes. The smaller panes used in the Comet and the Caravelle made their noses easier to shape. Modern designs use curved panes, and they produce no sharp edges which contribute noise.
Hello Rainer, I’m a high school student about to apply to Engineering. I was wondering whether you thought applying for general engineering and then specializing in aeronautics in the third and fourth year would be a waste of time compared to a 4 years solid aeronautics degree. I’m fascinated by the articles in this blog, but still unsure about whether I’d prefer getting to know all the different disciplines better before making a clear choice (especially because I’ve very intrigued by Mechanical engineering)or just throwing myself into aeronautics and hope for the best. Sorry for this confused comment! Love the blog though!
Hi Rainer, my name is Jorge Gerardo Aragón Villarreal, I´m mexican and currently live in Monterrey, México. I´m in the International Baccalaurete 2 year program and as part of it I need to make a research paper. Mine is about airfoils and I constructed a wind tunnel to make the experimentation. I´m lost in one aspect, however very important.
How I´m supposed to quantitatively visualize the critical angle of attack in an airfoil? is there any guide or criteria I could use to do it ? how can I determine if the angle of attack in a particular airfoil is , if i just have an wind tunel with smoke visualising ?
c
Hey George
http://www.dept.aoe.vt.edu/~aborgolt/aoe3054/manual/expt1/fig7.jpg is a good demonstration of how to get the quantative angle of attack. To be more precise you could think of a weighing system to calculate the lift and use Xfoil or just the airfoil data to correlate the lift and the angle
Hope you find this useful
Shrey
I stumbled onto your blog while looking for Aeronautical Engineering blogs and am very much enjoying it.
Hi Rainer,
Can you explain horizontal tail dihedral (or anhedral sometimes); what are the main drivers for rigging dihedral in a tailplane?
Hi Stephen, thanks for your comment. Sure, I’ll try to write a post about that soon. Cheers, Rainer
Hey Rainer! Awesome blog, congratulations!
Your aerospace hall of fame is great, I am here just to make sure you will remember aviation pioneer Santos-Dumont. He’s not so famous outside of Brazil, but certainly a great contributor to the beginning of aviation.
https://en.wikipedia.org/wiki/Alberto_Santos-Dumont
Hi George,
thank you for your comment, and I am glad that you enjoyed the post. Thank you also for the tip on Santos-Dumont. I will keep him in mind when I get to surnames starting with S 🙂
Rainer
Hi there, I will be starting a glider project university and am pre reading on lift, could you explain what this means as I am struggling to understand what it means:
“Bernoulli’s principle, i.e. along a streamline an increasing pressure gradient causes the flow speed to decrease and vice versa, is then invoked to deduce that the speed differential creates a pressure differential between the top and bottom surfaces, which invariable pushes the wing up.”
From your page on how to increase lift. Thank you!
Hi, thank you for your comment. What I am referring to in this comment is that Bernoulli’s principle is often invoked to explain why wings create lift. Bernoulli’s principle is derived from the conservation of energy along a streamline and states that
, where 
is the fluid flow speed at a point on a streamline, 
is the gravitational constant, 
is the vertical distance with respect to a reference plane, 
is the fluid pressure, and 
the fluid density. So the combination of these parameters between two different points along a streamline have to give the same result when plugged into Bernoulli’s equation. If you look at the equation and assume that the streamline is horizontal (so 
does not change), then a decrease in pressure 
means that to keep the equation constant we need an increase in velocity 
. So the bottom line is that if pressure falls between two points then the velocity must increase, and if the pressure increases between the two points then velocity must decrease. What I was referring to in that comment is that the (faulty) argument is often made that the flow over the top surface of an aircraft wing is faster because this surface is longer due to curvature, and for equal transit times the flow over the top surface must be faster than over the bottom. It is certainly true that the flow over the top surface is often faster than over the bottom surface (and hence from Bernoulli the pressure on the top surface must be lower than on the bottom surface, which creates a pressure differential that sucks the wing in the direction of the top surface) but this is not due to the argument of equal transit times but rather due to centripetal forces induced by curved streamlines as a argue in the article. Let me know if this clarifies the above point…
Hi Rainer,
I’m a big fan of your blog and studies. I found an article named “Boundary Layer Separation and Pressure Drag” and I was hoping I could use some of the information as part of my dissertation titled “UNDERSTANDING THE EFFECTS OF MIMICKING SHARK SKIN ON A WING IN REDUCING THE DRAG ON AN AIRCRAFT AND INCREASING PERFORMANCE AND EFFICIENCY”
Thanks,
Dylan Jannetta
Hi Dylan,
I am glad that you find the blog useful. Yes please, use any information you like. Good luck with the dissertation!
Thanks,
Rainer
Rainer, I’ve just been referred to your website. Congratulations on your using web technology to address many aspects of aviation-aerospace history and ongoing research and activities. I have an aero engineering degree and worked for a major aerospace company for 2 decades. When retired employees of that company gather for frequent gatherings, the funny tales fly back and forth. A half-dozen years ago I started collecting those stories and sending them to the past employees (who sent more stories). About 2-3 years ago I said it’s time to get these together in a different form of history of a major aerospace company. I’ve assembled those those stories in my recent book “Fun on the Job: True and amusing tales from Rosie-the-Riveters to Rocket Scientists at a Major Aerospace Company” from people employed over 8 decades at this one U.S. aviation and aerospace company’s
operation located in San Diego, California. At various times over 45,000 employees worked for this firm with names Consolidated Aircraft, Consolidated/Vultee, Convair, General Dynamics, Astronautics, Mission Systems and more. These operations turned out many products of importance, among them thousands of B-24 bombers, F-102 and 106 USAF Fighters, commercial airliners, Atlas and Centaur rockets, Tomahawk Cruise Missiles and many more. The many amusing stories here come from operations, products and locations throughout the U.S. and frequent overseas assignments. These jolly tales will stir readers’ humor buttons from their own work experiences, whether retired or currently employed. And needless to say, those with aviation, aerospace and defense ties will find many fun stories they’ll readily relate to.
Here are some comments about the book:
“Thousands of people spent millions of man-hours developing the Atlas. But not all of those hours were spent on space business— many were spent on funny business. People, being ordinary people, often had time on their hands. We Rickety Rocketeers at Cape Canaveral had lots of idle time between launches and we engaged in a lot of “Funny business.” Tom Leech has collected many stories of our mischief during those idle hours and provided them to you in this book. Read them and you will see that we were not all “Steely eyed rocket scientists.” — Leroy Gross, Head Rickety Rocketeer
“Fun on the Job” brought back memories of life at the “Rocket Factory.” We raced towards building planes and the Space Age with serious intent, but not without truly amusing stories. This book is flavored with the dynamics of exciting times and, is a “missile with a payload” of great entertainment. Reading the anecdotes, one can almost feel the pulse of the aeronautical industry of those years. (I’m still smiling!)” — Kay Quijada, 4+ decades at multiple GD assignments
“This book by Tom Leech is a must read for all GD San Diego Alumni for at least two reasons: It has some really funny anecdotes, but perhaps even more importantly, it brings back wonderful memories of our co-workers and of the great times we had in the years we spent together creating nationally important, state of the art products.” — Bill Vega, Retired VP of Research and Engineering, GD Convair Division
I invite your personal review of the book and will get a copy to you per request. It’s available in paperback and as a Kindle e-book, from amazon.com. More information is available at my web site below. I welcome the opportunity to discuss the book with you as well. Thanks for your attention.
Hi! I’m giving a presentation on turbofans at school, and I’d like to use some formulas and images from one of your articles (https://aerospaceengineeringblog.com/jet-engine-design/). Is that OK with you? If so, who should I reference as the author?
Also, great blog!
Thanks
Silas
Hi Silas,
glad that you are liking the blog. Sure, that is absolutely fine with me. In fact I encourage people to use the resources here as freely as possible (see here: https://aerospaceengineeringblog.com/about/copyright/). You can reference me, Rainer Groh, as the author. Good luck with the presentation.
Thanks,
Rainer
Hi! Sorry to bother you again, but I can’t figure out how you simplified the Np equation in 1.2. (on this page https://aerospaceengineeringblog.com/jet-engine-design/). Could you explain how to do that? I can’t get rid of a 1/Uj…
Thanks again! The blog has been a huge help.
Silas
No worries Silas. That’s a good question. If you look at the denominator of the
expression you will see the perfect square of 
, which can then be factored into 
. Now you can cancel the terms 
in the denominator and the numerator. Putting the 0.5 in the denominator as a 2 in the numerator, and cancelling out the mass flow rate you are left with 
. Hope this helps.
Of course! I can’t believe I missed that. Thank you!
No problem. Happens to the best of us 🙂
Hi! Great blog! I am an experienced structural engineer, but always worked on fixed structures, never aircraft. The recent Southwest Airlines accident in which a woman was half pushed through a window of a 737-800 piqued my curiosity as to how are windows attached to the frame. In principle, it would be easy to attach some retainer plates to the outside of the frame to avoid this kind of accident, with the obvious issues of additional turbulence, drag and fuel consumption. But shouldn’t it be already accounted for? Can you point me to a detail, or a description, showing how windows in commercial aircraft are attached to the frame, specifically whether they are retained on the inside (assuming higher external pressure) or on the outside (assuming higher internal pressure)? Thanks in advance!
Hi Ernesto,
great question! Unfortunately, the attachment of aircraft windows is outside my area of expertise, and I wouldn’t want to give you false information. However, you might find some useful information here: https://www.heritageconcorde.com/concorde-fuselage-windows
Thanks for reading,
Rainer
Hi,
I hope you will be fine.
I am PhD Research student. I prefer to work on drilling of IM7-8552 composite materials.
Most of the work has been done on findings of single drill bits. I have the poly drill spindle accessory of special purpose machine and want to work on simultaneous drilling using different drill bits.
But, I am now looking whether poly drill with simultaneous drilling is the part of aircraft production and in need of aircraft industry.
Could you please help me, If this is useful for the aircraft industry in saving their cost, time and will give then efficient and effective production so that I can include this a part of my PhD research with a compromise on good hole quality.
I will be very thankful for your assistance.
Thanks
Muhammad Aamir
Hello Rainer, I am Kashish, I’m a Bachelor’s student in Automobile Engineering. I am working on a project for which I need to understand some basic calculations related to Aerospace Engineering, and have to clear some doubts in Autogyro mechanism. if you could please guide me a bit, it will be a great help for me. I have these doubts;
How can we calculate the Rotor blade rpm related to wind speed and descent speed of autogyro?
How can we calculate the lift coefficient and drag Coefficient of the blade?
What Airfoil to choose, how much does Airfoil shape affect?
I don’t have much knowledge in Aerospace background, so I really need your help for a successful design, It will help me be a better Engineer. Kindly help me in any way you can.
Thank You
Hi Rainer!
I am an Aerospace Engineering student and I have been searching for information about the field and the career I will persude. I am really grateful to tou for such blog. I will spend my time here looks like, till I read everything in here.
I have a question tho, I am not quite sure about which way to go after I graduate. I love materials, I love aerodynamics, I love CATIA, I love engines. Do you have any opinions you could share with me about the future of aviaton as an experienced engineer?
Best regards,
Berkehan
Hi Berkehan,
thanks for your note. As a number of people have said: “Predictions are difficult, especially about the future.” So yes, it’s hard for me to say anything for certain about the future directions of aviation, or at the very least, to say anything with enough confidence that you should base your career decisions on. Every industry goes through phases of interest, and new fields arise that were hard to foresee. My general advice is always to become exceptionally good at a skill that is valuable to the industry, and to keep updating your skills so that you remain valuable. As Cal Newport has said much more elegantly, “Try to get so good that they [in this case aerospace companies], can’t ignore you.” The easiest way to do this is to notice the areas of study where you naturally excel, or those that come easy to you. In that way work will not feel like work, and you’ll be willing to work much harder at it than your peers and progress faster.
Hope this is helpful,
Rainer
Hi myself Thalesh Kashyap, a bsc physics (Hons.) Pursuing student , being excellent in physics but a little weak in mathematics , can I pursue carrier in aerospace engineering after getting my MSC degree and then moving to (ME AEROSPACE).
Hoping a reply from yours side .😁
Hi Thalesh, I would say that with a physics background you would have excellent pre-requisites for becoming an engineer. Physics is a very mathematical subject as well, so I would guess that your mathematics skills are sufficient for engineering. On the other hand, design, engineering heuristics, and manufacturing technology will be entirely new and will probably present a steep learning curve.
Hi Rainer,
Let’s say I would like to design a set of fan blades for a high bypass turbofan engine of a certain thrust requirement. Is there any books out there which could lead me to determine the size, shape and twist angle of the fan blade? Thank you.
Regards,
Hanlin
Hi Hanlin,
Turbines, Compressors and Fans by S.M. Yahya might be a good reference.
Rainer
Dear Mr. Groh:
I am searching for an aeronautical engineering book published in the 1941-1945 time frame that had to do with teaching engineers (from various fields) about aeronautics to quickly bolster the American war effort. (the quantity of aeronautical engineers being small in regards to those needed, based on all engineering having a base).
I can not remember the title or the author, but I believe it was an organization as opposed to one person. (Clue….I owned said book and have since lost it or loaned it)
Any help would be appreciated.
Bulldogbuilder.
Hi,
thanks for your comment. I don’t exactly know the book that you are speaking of, but the WWII effort to train engineers was called “Engineering, Science, and Management War Training” (see Wikipedia here: https://en.wikipedia.org/wiki/Engineering,_Science,_and_Management_War_Training). Maybe the book that you are looking for is referenced at the bottom of that Wikipedia article. Good luck and sorry that I couldn’t be of more help.
Rainer
Hi.i am a student studying in class 11. I want to become an aerospace engineer but my teacher
Is forcing me not take this career as it doesnt have any scope and there is lots of unemployment.what should i do.
I have very simple, perhaps stupid question to ask about coaxial contra-rotating propellers.
Do the two propellers in such a system give the same thrust as two separate propellors of the same size rotating at the same speed, or is the thrust about the same as a single propeller, also rotating at the same speed?
Dear Ryan, thanks for your question. I think the easiest way to think about this is in terms of energy and power. As you probably know, energy is a conserved quantity, and part of the energy provided by the engine is converted into forward motion through the action of thrust and the rest is lost to drag. In propellers one source of drag is rotational airflow, which does not contribute to axial thrust. So placing a second propeller behind the first one turns some of the rotational flow back into axial flow and thereby increases thrust and propulsive efficiency. Another way to think about this is that for a specific engine power rating (kW or horsepower) a greater proportion of the power of the engine is actually used to propel the aircraft forward.
Hi,
I just came across your blog when I was trying to do some maths and science at home for fun, and I was really interested in how you figure out the lift for certain object(s), but I did not really understand how to figure it out. Since my teachers are, well teachers that don’t have PhD’s in the topic, I would like to contact someone. Just someone who can help me.
and I wanted to figure out how you figure out Cl, but when I googled the formula for Cl, I got a formula that uses lift as a variable, the exact variable I am trying to figure out.
Hi, thanks for your question. The lift-coefficient is a non-dimensional form of the lift force, which is useful as it allows us to compare the lift production of different shapes even if they might be of different surface areas or subjected to different flow velocities and fluid densities. Lift is usually computed by integrating the pressure over the surface area of the body. There is a NASA webpage on the topic here: https://www.grc.nasa.gov/www/k-12/rocket/presar.html. To do this you require an expression for the pressure across the body, which apart from the simplest of shapes, is difficult to do. In this article here (https://aerospaceengineeringblog.com/how-do-wings-work/) I have outlined how the pressure field is computed for a streamline that moves in a curvilinear path of constant curvature, i.e. limited to one specific case. Sorry if this doesn’t answer your question.
Thanks for the help! (And you did answer my question.)
Hi Rainer
Love the podcast, I’m an unemployed aerospace engineer so unfortunately not a patreon. Could you try to give an interview to Snorri Gudmundsson. He’s done a huge bopk called “General Aviation Aircraft Design” an I think he is a professor at Embry Riddle and may have had a hand in the Cirrus Vision SF50.
Best regards
Mark
Hi Mark,
thanks for reaching out and I am glad that you enjoy the podcast. I will reach out to Snorri and ascertain if he is interested in an interview.
Thanks,
Rainer
LOL…I am happy to chat with you…Dr. Gudmundsson
I regularly visit the Aerospace Engineering Blog to learn something new about aerospace engineering. Congratulations on such a wonderful site & achievement!
I have the shell of an early engine here which has 7 combustion chamber nozzles similar your picture. Do you have information on this engine IE the make and model year etc?
From your blog:
Jet Engine Design: The Turbine
Hi Bob, thanks for your comment. I presume you mean the picture in Fig. 1 of Jet Engine Design: The Turbine. This is a sketch of a triple-stage turbine with a single shaft system. The multiple combustion chamber design is very common for many jet engines. Apart from Fig. 1 being a sketch, it would be hard to identify a jet engine just based on this single feature of multiple combustion chambers. The sketch of the triple-stage turbine in Fig. 1 of Jet Engine Design: The Turbine is most likely based on a Rolls Royce engine though.
Rainer
Hello I’m looking for an aerospace engineer to answer a few questions if they can. What got you interested in the field of Aerospace engineering in the first place?
Do you still enjoy your career after so many years in the field?
If you could go back in time, would you have chosen a different career and why?
Was it hard to find work in the Aerospace field after graduating from college?
What advice would you give students who are in school right now trying to become an engineer?
Hello, I am an aspiring aerospace engineer and I have a few questions I would like to ask
• What is your average work schedule?
• Starting with high school, describe your educational background chronologically.
• If you had it to do over, related to your career or education, would you do anything differently?
• What advice would you give to me as someone interested in pursuing a career path similar to yours?
Thank you very much for your time
I’m wondering if something like a Cessna 172 would benefit from wings curved at the end such as a passenger airplane? Is it because the wings are on top that they are not curved? I’m trying to think about why it wouldn’t but I am not too certain, could you spread some light on the subject?
Hi Austin, all aircraft would benefit from wing tip devices. These features stop the higher pressure air on the bottom of the wing from spilling up into the lower pressure air on the top of the wing. By stopping this, the lift generation of the wing is improved. As with everything in engineering, there is no free lunch and adding these features comes with extra complexity in design and manufacturing. Given the greater service life of commercial airliners (miles flown) the investment is much more worth it for larger aircraft.