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Murielle Percheron-Tramblay
Background and experience in oceanography (geophysics/biology), geomatics and environmental studies. Passionate about navigation & exploration technologies. Interested in the philosophy of technology.
Location Arcachon, Aquitaine, France
Achievements
Activity
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Murielle Percheron-Tramblay made a comment
@YvesGourinat @LeonardoSanches @Anne-LiseLuga
Thank you very much to the whole team for this very informative course! And when will it be accessible again on FutureLearn? ... because I didn't have enough time this time of year to complete it properly, thank you! -
@YvesGourinat
Indeed, I have seen that these complex numbers, the quaternions, which are more stable numerically and therefore more efficient in rotation movements, are also used in an inertial system based on gimbals such as navigation systems, so that orientation in a 3D plane can be correctly performed, and obtain the right orientation (without loss of... -
Thank you very much for the clarification!
Indeed, I forgot to mention that this example represents the movement of an articulated arm in static mode (lifting a weight)
From your explanations (and according to my understanding), considering the vector product of the moment, and since the movement induces a rotation, the resulting...
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Murielle Percheron-Tramblay made a comment
The moment of a force with respect to a given point is a physical vector quantity necessary to rotate a mechanical system around that point (the pivot), such as the articulated arm of a robot (picture). Thus, the moment (of the arm) is equal to the force (weight) multiplied by the distance of the arm to which the force (weight) is applied...
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Murielle Percheron-Tramblay made a comment
Phew! Some knowledge forgotten..., and after some revisions here and there, I was able to take the test with only 2 mistakes, and I didn't know if I should write the missing term in numbers or letters.
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@LeonardoSanches
Yes, if the force exerted on the solid is compensated by the reaction of the support (the table), such as a rough support for example, exerting an equivalent friction force. Thus we obtain :
Sum Fext = 0 then Sum Fext = Resultant F = 0
(sorry, cannot write the sum sigma and vector symbols) -
Murielle Percheron-Tramblay made a comment
This may be far from this course, but static or dynamic concepts and situations can be extended to the univers, as a system:
Is dark energy static or dynamic? by L Zyga
"While hypothesized dark energy can explain observations of the universe expanding at an accelerating rate, (its) specific properties are still an enigma. Scientists think that dark...
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Murielle Percheron-Tramblay made a comment
In any case, if an object does not rotate around its axis (fixing point) despite the force exerted, it is observed that the situation remains static (static torque). Or when cycling at a constant speed, a static torque is applied because you do not accelerate.
And people use dynamic equilibrium when climbing ladders or walking on the beach because they... -
@Anne-LiseLuga
Bonjour Anne,
De retour, curieuse d'en apprendre davantage / I am back, curious to learn more about this field ;-) -
Murielle Percheron-Tramblay made a comment
Hello, graduate (master's degree) in oceanography (marine geophysics) and environment, living in Arcachon, France, I am very interested in naval, aeronautical and aerospace engineering as well as its implications in the philosophy of technology. I have enthusiastically taken the "ABC of Flight Mechanics" course taught by Eric Poquillon, so I want to learn more...
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Indeed, the Qiantang River in Hangzhou, China, is especially known for having the world's largest tidal bore, and also great... to surf ! ;-)
In French, this wave formed bears the pretty name "mascaret". -
Murielle Percheron-Tramblay made a comment
The Ocean. The last space left to be explored in its deepest depths on this blue planet. Where the interrelationships between living beings, and with the elements that constitute this unique dimension, are undoubtedly even closer in the fluid element. This makes it more difficult to prioritize one area over another.
The ocean is a changing and adapting...
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The Ocean. The last space left to be explored in its deepest depths on this blue planet. Where the interrelationships between living beings, and with the elements that constitute this unique dimension, are undoubtedly even closer in the fluid element. This makes it more difficult to prioritize one area over another.
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Murielle Percheron-Tramblay made a comment
First of all, just as there are laws against trafficking and trade in exotic species, the trade in shellfish and marine species (harvested and dried for sale) in tourist souvenir shops should be prohibited. It's always shocking to see how obvious the massacre and looting are! The supply preceding the demand, the end justifies the demand. In the meantime, we...
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Exactly! And I have a smartphone that is already over 4 years old, and I maintain it quite well. Fashion, I don't care about that ;-).
However, the problem is that there are still serious capacity limits that pose real problems of use (since a product with higher RAM will very often have a higher (prohibitive) price!), and in addition, as I have already... -
I agree with that. And most of the time, my smartphone stays at home when I go out (I bike, dive,...). So, you can enjoy technology, and on the other hand explore nature on your own too ;-)
That said, it doesn't solve the problem of the phone's memory anyway, and the one occupied by major applications that are too greedy... -
@TimShipway The problem is that some applications, for example Ytube, or Yahoo, etc, cannot be moved on SD cards in some (relatively) old smartphones. And even if you can transfer several of them to the SD card, a lot of data - as well as video data - is managed by the phone's RAM, certainly depending on the type and brand of the smartphone.
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@Wenhao Wang
Indeed, there are two types of ridges:Fast ridges (maximum opening 18cm/year) with many event sites but small and unstable, and large deposits that are several km from the rift, due to volcanic eruptions, especially in subduction zones.
And the slow ridges (opening 2cm/year), such as the Atlantic Rift, with few vent sites but stable and...
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Murielle Percheron-Tramblay made a comment
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1) Rare metal concentrations are estimated to be quite contrasting depending on the type of mineralization, but also on the environment in which it is formed.
The base metals contained in nodules are mainly iron, manganese, nickel, cobalt - and copper is on average in concentrations twice as high as those of large copper mines in the Andes! Since these... -
Murielle Percheron-Tramblay made a comment
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3) Continued…
...even if the mineralization potential of vents is gigantic - since this hydrothermal circulation would be equivalent to the total volume of the oceans on a scale of 8 million years - wouldn't mining operations risk drastically disrupting these activity cycles, also taking into account physico-chemical interactions ?And is it possible...
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Murielle Percheron-Tramblay made a comment
For information :
According to a report commissioned by WWF from the University of Newcastle (Australia). Each individual would ingest 5 grams of plastic each week through water, especially if it is bottled, then through seafood and salt! (Ref. "Le marin", June 20, 2019) -
@HannahSharman
I am not so surprised that the recovery of a healthy balance can be so long for these benthic species living in these extreme conditions, and often endemic, dependent to the same place of life.
And this is often proportional to the drastic changes that can occur because of critical pollution thresholds that are exceeded faster than in other... -
Murielle Percheron-Tramblay made a comment
A cure (difficult to apply), but not the solution to stop the plastic waste inputs to the ocean, anyway...
"A floating device designed to catch plastic waste has been redeployed in a second attempt to clean up a huge island of garbage swirling in the Pacific Ocean between California and Hawaii.
(...)
Floating boom is designed to trap 1.8tn items of... -
Yes, Salyna, packaging (bags and commercial packagings) is a real problem, often with superficial and unnecessary double packaging, and must be resolved at the political level as well (especially those which are made by industries).
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Murielle Percheron-Tramblay made a comment
Our plastic pollution crisis is too big for recycling to fix – Annie Leonard
As it is said in the article, and shows in the infographic about plastic waste inputs to the ocean, I think that the overall production of plastic remains too...
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Murielle Percheron-Tramblay made a comment
Just for information, on 1 January 2018, France introduced a ban on the import, manufacture and sale of microbeads in rinse-off cosmetics.
Uk ban on the use of microbeads in rinse-off cosmetics and personal care products. England and Scotland (19 June 2018), Wales (30 June 2018), Northern Ireland (1 October 2018).
Canada, ban on microbeads smaller than 5...
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I'm glad you appreciate it. I also like to share all this additional information ;-)
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Indeed Hannah, the article specifically mentions the strong impact of the Humboldt current. And climate change... will this indeed change the situation ?
Yes, this general oceanography course (which makes it unique and brilliant!), allows me to review my knowledge (and especially to update it) of what I have long been passionate about: the marine world... -
Right, it shows only a quantity and not a distribution by country. Although it is quite difficult to determine the origin of each cigarette on a beach full of tourists...
If I compare with Canada, in France, single bottle use (especially sodas) remains less important. And even if plastic and metallic bottles are recycled, a large part of all plastics is... -
Murielle Percheron-Tramblay made a comment
I have an old converted laptop and I learned on the job to program, but now I'm really going to have to change it...
I have a smartphone that is 4 years old, thanks to a regular maintenance that I bring it, there is no need to replace it. The major problem is the constant updating of applications that can make smartphones obsolete.... >:-( -
Murielle Percheron-Tramblay made a comment
Not easy to determine the most significant human impact in the deep-sea, because it is a combination of different types of human activities, like deep-sea fisheries and pollutants, or even extractions. Chemicals can be really toxic to deep-sea species. Two years ago, scientists discovered extremely high levels of toxins at depths of more than 10,000 m in the...
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@MargaretHunter
Yes, cigarettes are much more polluting than we think...
Cigarette filters degrade very slowly - on average one to two years. And one of its components, cellulose acetate, is a plastic that takes more than ten years to decompose.
According to the Butt Pollution Project Cigarette, the majority of the 5,600 billion cigarettes manufactured... -
Yes, you are right. It is exactly "a throw away society" where the value of a healthy economy, and the sense of conservation to avoid easy waste, is to be relearned. But "the sense of measurement" must also be reintegrated on the side of industry, producing technologies with programmed obsolescence....
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Murielle Percheron-Tramblay made a comment
The very progressive trend of the collector's curve - of deep-sea vent species, has challenged me despite the sophistication of technologies since 1977, demonstrating that the exploration, and discovery of new marine species living in extreme environments, remains a major challenge! In particular, with regard to having enough data to protect these habitats...
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Murielle Percheron-Tramblay made a comment
Phew... not easy to choose, especially between the deep sea (my choice), which represents the largest unknown part of the iceberg of our knowledge, as well as for the technical implications of exploration, and the open ocean for a better understanding of the behaviour of marine animals and their interactions...
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The curve does not seem to have reached its constant level yet. This is difficult to predict because even if there were three and a half times more discoveries between 1987 and 1997, the curve then becomes very gradual with an average of just over 13 new species per year. In addition, it must be taken into account that access conditions remain difficult... and...
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Murielle Percheron-Tramblay made a comment
This deep-sea fish is holding its breath underwater!
Chaunacids, which can reach 40 centimetres in length, live in the abyss between 200 and 2,000 meters deep. Like other lophiiforms, exhibit highly specialised ventilatory anatomy such as an enlarged branchiostegal apparatus and restricted gill openings, but videos from ROVs show them using this anatomy in...
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Murielle Percheron-Tramblay made a comment
Very surprising to note that the Hector's dolphins, the smallest and rarest marine dolphins in the world, occupy a territorial range of 52 km, only around New Zealand. They never going far from where they are born. Recent surveys estimate about 7000 animals, but threatened by fisheries bycatch, pollutants and boat disturbance....
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Murielle Percheron-Tramblay made a comment
Shaped by fluid dynamics !
Using elementary hydrodynamic arguments, the researchers uncovered a unifying mechanistic principle and derived a compact formula modeling 50 years of empirical observations.Characterizing the locomotion of every aquatic swimmers by deriving a scaling relation that links swimming speed to body kinematics (tail beat amplitude and...
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Christiane Guinot ... rockpooling = soulever des roches ;-)
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Murielle Percheron-Tramblay made a comment
The both polar environments (Arctic or Antarctic) are rich and important in biodiversity, as well as in climate regulation. Impossible to choose...
Although, as I am also Canadian, I feel closer to Arctic environment with a diversity of animals of every sizes. Moreover, it is more connected to the inhabited places, and other ecosystems such as the tundra....
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Hi Hannah, actually, after a short research, there are two issues responsible for the lack of seagrass beds.
There is indeed an explanation related to human activity such as cattle raising, intensive agriculture as you mentioned – and product spills can cause eutrophication of marine ecosystems – as well as coastal development which has resulted in resorts...
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Murielle Percheron-Tramblay made a comment
Faced with global warming, all forms of life in the poles must face a new ice melting record every year! Recently, Greenland lost 2 billion tons of ice in one day, comparable to the record-setting ice melt in 2012.
https://edition.cnn.com/2019/06/14/us/greenland-sudden-ice-melt-wxc/index.html
Huge losses of ice pack also represent a huge loss of hunting... -
Murielle Percheron-Tramblay made a comment
Amazing ! The treasures of the sea...
Very interesting article about the amazing pharmacopoeia of several coral species, but also about the surrounding species (anemones, gorgonians, sponges, etc.) It is technical but it is worth looking into :
"Several target enzymes have been used as assays for anti-diabetic (α-glucosidase), immunosuppressive and... -
The distribution of coral reefs appears to be widely distributed, up to polar latitudes!
And fortunately! Because as Dr. Katleen Roberts* says in her article, many other species are found in close proximity to cold-water corals. Probably "that cold-water coral presence leads to higher biodiversity, and possibly provides complex habitats for other species to...
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Arguments in favour of scenario 2 as a balance between ecological and human issues :- It can take years for anchor scars to disappear, and they often accelerate the loss of seagrass beds by facilitating erosion at the edge of the scars. Thus, even if seagrasses can regenerate and grow back in these scars, it takes time and also depends on the...
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Arguments in favour of scenario 2 as a balance between ecological and human issues (continued):I have worked on the multiple uses of the marine space, and boaters are not necessarily more inclined to get involved.... And the costs associated with the ship are already significant. But precisely, it is therefore necessary to involve a minimum number of...
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Murielle Percheron-Tramblay made a comment
The Pacific coasts of North and South America seem to be poor in seagrasses ... Is it partly due to the climate, to the land-based or water components of the seabed - apart from intensive fishing?
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In my area, I have observed in 10 years a decrease in the presence of sea algae deposited on the beaches, certainly caused by the multiple uses of the... -
Murielle Percheron-Tramblay made a comment
On the picture, I can see a dozen drill holes, well circular, made on different mussels, but they must certainly be more numerous. This whelk was definitely hungry ! :-D
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Rockpooling is a fun and educational activity because it arouses curiosity and reflection IF it is practiced with care. Because the feeling of discovery is mixed with the feeling of... -
There are a minimum of a few hundred billion stars per galaxy, and a few hundred billion galaxies, then by making the product of both, we find that there are about more than 10^22 (10 power 22) stars in the observable Universe (probably max 10^24)
The global ocean contains approximately 4.4 x 10^28 living microbial cells, they are therefore the most numerous. -
Murielle Percheron-Tramblay made a comment
Half surprising since the combo "cigarette-drink-food" is the common on the beach, unfortunately. I can easily check it here on the beaches of the "Bassin d'Arcachon" (southwestern France), especially in summer ! :-(
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Murielle Percheron-Tramblay made a comment
A whole world in a drop of sea water !
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Murielle Percheron-Tramblay made a comment
First of all, this course allows me personally to carry out a good review of oceanographic knowledge, as well as an essential update ;-)
I note that many observations remain to be made and studied, particularly in the interrelationships and their consequences between and in the different fluids (atmospheres and seawater), and especially relating to the...
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Murielle Percheron-Tramblay made a comment
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I participated as a research assistant on the study of sea level rise in New Brunswick, Canada, about 15 years ago... The effects are amplified because of the subsidence of this part of the Canadian continent, and they can be impressive. For example, I saw the terrace of a house crushed by ice when the icy waters broke (in the north)! , or completely... -
Murielle Percheron-Tramblay made a comment
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Good image to visualize the sea level rise in N-B
https://www2.gnb.ca/content/gnb/en/departments/elg/environment/content/climate_change/content/climate_change_indicators/indicators/water/sea_level.htmlAtlantic Canada on irreversible path to significant sea level...
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You mean by enhancing the food supply of coral polyps (animals) ? since they feed on food particles in the water essentially sunlight-trapping microscopic algae called zooxanthellae, which are embedded in their outer surfaces (Exoskeleton).
Not easy on a large scale I guess. But I found this... -
Murielle Percheron-Tramblay made a comment
This descent to the deepest depths, of surface waters rich in oxygen and carbon dioxide, also ensures the renewal of oxygen in the deep waters, giving the possibility of living there, and the transfer of the carbon pumped into the atmosphere.
Actually, I have often heard that it takes between 1500 and 2000 years for a particle of water from the Norwegian...
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Yes, it is fascinating and it also concerns geomorphology, and how the seas and oceans have shaped the landscape. Various marine shell fossils are also still found in the mountains, and this is linked to the mechanism of mountain formation, for example in the Alps: "In the secondary era the Alps did not exist. Instead, there was an ocean at the bottom of which...
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I would like to say not to consider math as a taboo (especially women, go beyond prejudices ;-)), it's just a rule of three to do, anyone can do it!
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Sure, it is a good wave to surf ! but in Bay of Fundy it is also very cold, brrr.... :-D
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Murielle Percheron-Tramblay made a comment
As I previously said, in fact, after evaporation we would get approximately the equivalent of a 22-storey building! (if we consider the standard of 2.7 m per floor).
The average depth of the oceans is approximately equal to the square of the salt thickness (after total evaporation).
In comparison, the ocean surface area is approximately 662 times larger...
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Murielle Percheron-Tramblay made a comment
In fact, after evaporation we would get approximately the equivalent of a 22-storey building! (if we consider the standard of 2.7m per floor).
I would like to say not to consider math as a taboo, it's just a rule of three to do, anyone can do it!
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Murielle Percheron-Tramblay made a comment
"where are the largest tidal ranges in the world?"
I think (maybe one of the places...) it is in the Bay of Fundy, southwest shore of Nova Scotia, Canada. The height of the tide difference ranges from 3.5 meters (11ft) along the shore ! And I have been there since I lived not so far... ;-)
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Murielle Percheron-Tramblay made a comment
The ocean, our future !
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Murielle Percheron-Tramblay made a comment
I like the human point of view of Sylvia Earle about the huge unknown part of the ocean :
"...And only three people have made that journey to the deepest place, 11 kilometers [or seven miles] down (Mariana Trench, off of the Philippines).
The first excursion was Jacques Piccard and Don Walsh in 1960. Then in 2012, filmmaker [and National Geographic... -
Murielle Percheron-Tramblay made a comment
I found interesting convergences between ocean and space research :
"Most life forms that are relevant to studying habitability on other planets are expected in some environments that are similar to ones found in the deep sea. Deep-seafloor surface sediments are of particular interest because both pelagic and sediment species aggregate there, providing a...
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Murielle Percheron-Tramblay made a comment
Actually, the scientists who organized the Challenger expedition had assigned themselves the mission of exploring, half a century apart, the Atlantic islands studied during the Beagle's voyage. The Challenger therefore approached at the main points illustrated by Darwin's early research.
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Murielle Percheron-Tramblay made a comment
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The ocean, by its immensity, has long frightened us like a space of mortality, whether it is for communication or fishing. A too vast a body of water, moreover undrinkable, inexplicable because unfathomable, powerful, unpredictable and frightening, the ocean has thus become a reservoir rich in symbols and beliefs combining anxiety and curiosity. The sea... -
Murielle Percheron-Tramblay made a comment
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Still perennial, monsters have nowadays been transformed into Jurassic animals, or into known contemporary real animals, some of which are fished, such as those in the Bay of Biscay, here in Aquitaine: dolphins, tuna, conger eels, octopus, spiders... as well as Newfoundland whales inhabiting the legends of Basque fishermen. However, these sea monsters can... -
Murielle Percheron-Tramblay made a comment
The ocean and the sea is a world in itself, where beings and elements compose the multiforms of water. And this makes me feel to belong to this world.
A renewed presence, never the same and yet regular, essential to my daily environment. -
@GonzaloZarate Glad if I could help ;-) Yes it is indeed a barometric altimeter, and it is calibrated the same way.
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Mathematics may seem difficult, but the equations are very similar (perhaps from my point of view and knowledge), but as you say, the number of parameters to be integrated is important, and the overall picture (the aircraft in flight) not so easy to understand. This last point was the most difficult for me;-) and also exciting.
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Murielle Percheron-Tramblay made a comment
Just for the fun, I would say that it is fascinating that since my great-uncle Maurice Percheron published his book in 1921 : "L'aviation de demain, Télémécanique, La direction des avions par TSF", before successfully experimenting two years later, with his partner Captain Max Boucher, the first functional prototype of the "drone", until the current electric...
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Actually, by intersecting the air and water environments, the tail of the torpedo fish makes oscillations that extend over the whole body (trapezoidal) to the base of the head ! Thus, the whole body adapts to the fluid, allowing a more efficient and faster movement.
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Yes, and that's unfortunate! So, wishing for feedback and improvements on this point.
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Murielle Percheron-Tramblay made a comment
I don't know if there's the same in English, but I also like the comic book versions on aeronautics made (in French) by the author Jean Nicolas "Mon Premier Brevet Aeronautique (BIA)" (Eds Cepadues, 2017), to prepare the aeronautical initiation certificate : Aircraft, Aerodynamics and Flight Mechanics, Piloting, Meteorology, Navigation, Regulation, Safety, Air...
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Murielle Percheron-Tramblay made a comment
Thank you very much for this course, and the good teaching didactics, as well as these last reminder keys!
For me, the difficulty is above all the large number of parameters not only to be linked together but especially to be visualized in relation to the movements of the aircraft and the different flight situations. Actually, that's what makes it so... -
No problem ;-) Actually, a review of the basics of physics is necessary for this course, which is the case in the chapter 1.17 ("Newton's law").
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When cycling, a high speed, even a low steering angle, causes a rapid lateral displacement of the ground contact points; at a much lower speed, larger steering angles must be used to achieve the same effect so quickly and therefore maintain balance. And in this case, that's why it's easier to stand on the bike's pedals.
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Murielle Percheron-Tramblay made a comment
The major difference between a car and an aircraft is not necessarily the margin of error (as can be seen in accident statistics) but above all that errors can have fatal consequences while piloting an aircraft: the falling distance is not the same ;-)
However, in terms of concentration, it all depends on the type of aircraft, for which trajectory and for... -
Murielle Percheron-Tramblay made a comment
The aircraft designed and built by Bertrand Picard and his partners is made of carbon fibres (ultra-light materials) with a wingspan of 72 m and a weight of 2,300 kg! The 600 kg of lithium batteries are indeed recharged by day by a 270 m2 photovoltaic surface (17,248 cells!), and therefore allows to renew the energy during the flight, unlike motorized...
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Murielle Percheron-Tramblay made a comment
" Can gliders fly the same trajectories as planes ? "
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The main difference between an aircraft and a glider is the power source. In addition, an aircraft's flight time is limited only by its fuel supply, while a glider's flight time and trajectory are entirely dependent on the behaviour of air currents, especially updrafts. However, if the latters... -
This means that whatever the "Track" of the aircraft (north, west, east,...), the chi χ angle between the velocity vector and the geographical north (in a ground reference system), does not really affect the mechanics of flight ("the aircraft is flying exactly the same way"), but essentially concerns navigation.
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Murielle Percheron-Tramblay made a comment
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For my own purpose, I want to recycle this little and cute (spatial) aircraft : M2-F1 Lifting Body (Nasa, 1964)
:-D
"A lifting body is an aircraft that relies for lift on the shape of its fuselage, not on protruding wings. Many early lifting bodies were triangular as viewed from above and "tubby" as viewed from the side. The latter characteristic... -
Murielle Percheron-Tramblay made a comment
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Today, ironically, MIT and NASA researchers have jointly developed an aircraft wing that uses the same torsion system to modify the aircraft's trajectory and, above all, to optimize flight performance.
No more ailerons, then, but also no more flaps to change the wing profile at low speed and avoid stalling near the ground. Even better, the fuselage... -
Murielle Percheron-Tramblay made a comment
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Difficult to separate the both domains, actually.
I think at the very beginning the vision of flying through a aerodynamic model was predominant - as well as relating to the progress of the engine knowledge and function.
So, people tried really "to fly" like bird, and as propeller and engine technics progressed, they finally realized as propelling was... -
(Sorry for the late comment, but my PC has crashed).
@AdPluijmers ....I'm glad my explanation could help you.)
@EricPoquillon
In fact, I might suggest you to develop the exercise statement a little more. That is, under flight conditions, indicate that two atmospheric states (one standard calibration and the other real) responding to two equivalent... -
Murielle Percheron-Tramblay made a comment
I really appreciated the explanation of physics applied to the mechanics of flight, and especially the good didactic way of teaching it. Documents in pdf format, and of course flight demos are also very helpful ! Everything is clear and not confusing, which is not obvious in itself.
On the other hand, perhaps would it be more appropriate to include in the...
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Murielle Percheron-Tramblay made a comment
Stalling is probably the major risk when flying at low speed, and since at low speed the angle of attack is high, there will also be the risk of collision with the ground during landing, for example - and with everything at low altitude in particular. Thus, a second regime flight in these conditions can be problematic and, according to my research, cause the...
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2) The same with the PG law :
ρ std x r x T(k) std = ρ real x r x T(k) real
Then you get :
ρ std /ρ real = T(k) real / T(k) std
Finally, you can substitute the ratio ρ by the ratio T(k) in the fibal Hydrostatic equilibrium equation :
∆Zgeom = ∆ZP x T real ( T std +30 (or - 30)) / T stdI hope it's ok...
Sorry for this confusion. You were right to... -
Hello Gonzalo,
You say « ΔPs/ ΔPgeom = ρ_stand ⋅ ΔZPs / ρ_real ⋅ ΔZgeom
Hence ΔZgeom = ( ρ_stand x ρ_real) x ΔZPs x (ΔPgeom / ΔPs). Why the pressure variations ΔPgeom and ΔPs are equal? »1) Since "the Hydrostatic Equilibrium of the atmosphere, completely define the temperature, pressure and density of air ρ at EACH ALTITUDE", you have to consider two...
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Thank you - You're welcome ;-)
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The incidence varies much faster with speed when it is low than when it is high. Ex :
. between 60° and 70° => difference = 7.8°.
. between 160° and 170° => difference = 0.2°. -
Yes it is a double work !
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I have not really heard about any of these points, but I found something very interesting about flutter :
" The flutter problem dates back to the early days of aviation, sometimes with the disintegration of aircraft in flight or the loss of fins torn off by vibration at high speeds. Not knowing the technical reasons, the engineers then increased the structure... -
Happy that it could help you. :-) Anyway, a mathematical demonstration is necessary to understand many problem in physics, and especially in aeronautics !
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Murielle Percheron-Tramblay made a comment
1) During the flight by maintaining the aircraft in a vertical plane (bank angle = 0), in descent (push-over) to balance the weight that is vertical, the component of the lift opposite the weight must be of the same strength. This means that the lift itself is less than the weight and the load factor is slightly less than 1, therefore not far from 1 g.
2)...
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Hello Zoe
First, you need to refer to the chapter : Atmospheric physics
https://www.futurelearn.com/courses/flight-mechanics/1/steps/482143
"At higher altitudes...the Perfect Gaz Law and the Hydrostatic Equilibrium of the atmosphere, completely define the temperature, pressure and density of air at each altitude."
First, you have two states to consider in...
