## Open content approach to academic writing

A comparison between textbook creation under the open content license and the traditional academic writing shows that the open content is much more powerful. The open academic writing is extension of the traditional academic writing in which an article or a book is given to a committee for review. Only if a select anonymous members committee approves the book it is published. Supposedly, the committee is to make sure that minimum standards are achieved and also to improve the article. In the open content the a whole community acts as the ``committee.'' My past experience has shown that members in this select and anonymous committee have foreign reasoning, and only the sun light can eliminate these foreign reasoning. More importantly, the committee made of the whole community also provide enormous amount of feed back that accelerate the change the published material very fast. The study of the oblique shock demonstrates these points.The oblique shock study has been carried during the last 100 years or so. The oblique shock is considered to be the main part of the curriculum of many engineering disciplines like mechanical, manufacturing, chemical, and civil engineering. In aeronautical engineering, this topic is of extreme important and is major part of at least 5 different classes.

The oblique shock is dealing with a physical phenomenon of the flow of compressible substance above supersonic velocity over positive inclined plane (see the Figure ?). When the incline angle is negative (the plane turn away from the flow) the flow turn around the corner without a shock (Prandtl-Meyer Flow). The question when the flow undergoes a oblique shock or when the Prandtl--Meyer flow occur was never really settled. Additionally, when the incline plane angle increase above a certain value the oblique shock turns into detached shock (different kind shock). The detached shock is a shock that does not touch the body (which affects the resistance). While the value was known, there was no mathematical explanations for it.

During the World War Two, there was importance to having airplane flying faster than the speed of sound which is physical barrier that was cause by the shock. There are several kinds of shocks and some view the most important as the oblique shock. Consequently, many governments and agencies pour money to delve this phenomenon.

NASA sponsor researched into this problems and produced a famous report known as NACA 1135 which declared that the oblique shock's problem no analytical solution can be obtained. Since this challenge declaration was put into the open, countless people have attempted to solve it. And in the tradition of compressible flow, everything of significant has to be discovered several times before it accepted as “discovered.” The first one to discover the analytical solution was Briggs, J. after 8 years after the challenge was issued. Six years later, for the second time it was rediscovered by Mascitti, V.R. The emergence of the new mathematical approximation tools had “buried“ these two solutions for the next thirty years. And countless thesis's using small perturbation, artificial viscosity, etc were implemented to solve this problem. However, the “hand waving“ presentation in classes daunted the scientific community and the solution was rediscovered again by Wolf, T., (1993). And of course that was not enough it has to rediscovered by George Emanuel, (2000).

At this stage, the information about the discovery had some penetration into the field and it started to appear in another book Anderson's book. However, examination of many books since that date shows that whole the rest of the authors were not aware of the analytical solution. For example, every popular books published in this millennium show no reference to any of analytical solutions. In fact, one can not be sure that no another analytical solution published somewhere else. It is interesting that the authors of all these variations solutions believed and emphasize the usage of the analytical expression to obtain the numerical value of the solution. None of them saw the real importance of the studies the limits of the solution or when it is applicable.

Again, in early 2003 Bar-Meir rediscovered the solution. However, there was a twist to the way the solution was presented. As oppose to the previous authors presented their solution only in academic publication, this time the solution was published in an open content publication. In this open content publication, a dialog between the author and his readership was very strong as opposite to ``committee'' (peer reviewers) that approved all the other publications. The difference between the two publication methods turned out to be astounding. Numerous people attacked, criticized, scrutinized, and enhanced and the solution (even the author). As result, the solution was enhanced from version 0.3x of the book to current version 0.4.4.2

The difference of Bar-Meir's solution to all the previous solutions is not that there is any different numerical solutions. However, this difference is in the importance of better understanding of the physical phenomenon and its limits. Now the boundaries of the oblique shock model can be explained without resulting into ``hand waving.'' For example, the detach shock wave can be explained why there is detached shock with having, the students scratching their heads. More importunately something that was a puzzle before can be explained. The oblique shock occurs when the inclination is possible (see figure ). However, what happened when the inclination plane is zero or even negative. No one really solved this issue even though numerous works were carried assuming that there is a solution. Bar-Meir's solution was able to demonstrate that no oblique shock can occur when the inclination is zero, by default voiding the significance the numerous Ph.D's thesis.

The interesting the part of Bar-Meir's solution is that was never published in any scientific paper and yet was read by numerous practitioners and students in the field. Thus, rediscovering the analytical solution to oblique shock will be now like rediscovering the calculus. The power of the distribution of the information via the open content is much faster and wider than the regular academic publication system. Another important part of the way the material was published is who learn about it first. In the tradition publication the establishment like old professors who are acting as the reviewers learn about new information first. Later, they pass this information to the rest of the community especially to the students. In the new system, the students and many practitioners in the field know about it long before the establishment even aware that a new idea has brought to forefront.

Thus, the open content process moves the power of knowledge into the mass and remove the continuous rediscovering, so that improving and enhancing the solution be carried out right way.

- Briggs, J. ``Comment on Calculation of Oblique shock waves,'' AIAA Journal Vol 2, No 5 p. 974, 1963.
- Mascitti, V.R. ``A close-Form Solution to Oblique Shock-Wave Properties,'' J. Aircraft 6, 66 (1969) ``A close-Form Solution to Oblique Shock-Wave
- Wolf, T., ``Comment on `Approximate Formula of Weak Oblique shock wave angle,'' AIAA J. 31, 1363 (1993).
- George Emanuel, analytical fluid dynamics, crc press (2000)

### About Potto Project

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