Growing up, young people often hear the phrase "knowledge is power." This phrase originally appeared in Latin as "scientia potentia est" and is attributed to Sir Francis Bacon way back in 1597.

Having access to the right information can save you time, which in most businesses, translates to saving money as well. ESDU offers design methodologies that have been validated by technical committees. Using these methods can add up to a large resource savings.

Such is the case with a major aircraft manufacturer. When the FAA issued a directive to redesign fittings, the use of ESDU methods saved time and effort worth more than a million dollars. Engineers were able to use existing data and methodologies in their designs and calculations.

You can read the full story in this case study. For more information on ESDU, visit www.ESDU.com.

Did you know that there are regulations regarding aircraft noise? Software is a valuable tool for predicting what aircraft might sound like in certain scenarios.

ESDU software estimates the change in coaxial jet noise spectrum levels when moving from stationary to flight conditions. The method breaks up the coaxial jet mixing noise into three discrete single-stream jets:

1. The secondary jet
2. The mixed jet
3. The interaction jet

Each of these discrete jets is characterized by different combinations of the coaxial jet parameters.

Considering velocity alone, the single-stream jet that represents the mixed jet has a velocity that is a function of the velocity ratio, the temperature ratio and the area ratio of the coaxial jet.

The velocity of the interaction jet is taken to be the same as that of the primary (core) flow of the coaxial jet, and the velocity of the secondary jet taken to be that of the secondary (fan) flow of the coaxial jet.

The other parameters of jet temperature, jet flow area and jet diameter are treated in similar but individual ways.

The noise from each source is predicted, modified, and summed to provide a static coaxial jet noise spectrum.

Read more about this topic in an IHS Engineering360 interview with Cyrus Chinoy, head of EDSU's Aircraft Noise & Structural Dynamics Group, and Willie Bryce, a member of the organization's Aircraft Noise Committee.

In this series from IHS ESDU, challenge questions will be posted for the community. Some questions may require calculations and others are general knowledge questions.

Here's this week's question:

The use of oil flow visualisation as a means of identifying flow features can be a valuable tool to aid the analysis of the aerodynamic characteristics of a configuration. In this process, acenaphthene is used to:

a) show boundary layer transition in low-speed tests by evaporation

b) show boundary layer transition in high-speed tests by sublimation

c) show flow direction near the model surface by streaking

Check back soon for the solution to this question! Visit the IHS ESDU website for more information about the validated design methods, or to request a trial subscription.

In this series from IHS ESDU, challenge questions will be posted for the community. Some questions may require calculations and others are general knowledge questions.

Here's this week's question:

Which type of parachute would be suitable as an aerodynamics decelerator to reduce an aircraft's landing role?

a. Conical(solid fabric)

b. Hemispherical (solid fabric)

c. Conical (ribbon)

And the answer is:

c) conical (ribbon). Only designs with high levels of geometric porosity can deliver the stability requirements of this application. See ESDU 09012 for more information.

Visit the IHS ESDU website for more information about the validated design methods, or to request a trial subscription.

In this series from IHS ESDU, challenge questions will be posted for the community. Some questions may require calculations and others are general knowledge questions.

Here's this week's question:

An aircraft is flying at a geometric height of 10000 m at a geographic latitude of +10°. What is the geopotential height?

And the answer is:

9959 m. ESDU 77022 contains the relationship for calculating the geopotential height for a given geometric height and geographic latitude.

Visit the IHS ESDU website for more information about the validated design methods, or to request a trial subscription.