PDF Publication Title:
Text from PDF Page: 056
Chapter4. DataAnalysis 44 (a) TOB 10000 Hz. (b) TOB 20000 Hz. Figure 4.1: Harmonic aliasing effect evident in SODIX plots of TP DLR 317. The effect seen in Fig. 4.1(a) and 4.1(b) respectively, distorts the SODIX results to a certain degree as the SPL values drop significantly in the primary wake area of the nozzles. It is questionable, whether this effect represents physical phenom- ena or is an error either in the raw data itself or on SODIX’ side. At first glance, it suggests some form of spatial aliasing, as it appears to have harmonic qualities and only occurs for high frequencies, when the wavelength is short. Spatial alias- ing effects are prone to occur due to spatial undersampling of the sound events. The microphones in the linear array are spaced at constant intervals, which could potentially be too wide for high TOB, as the length of the sound waves decreases with increasing frequency. A possible criterion to assess this phenomenon is the trace wave length λs (Eq. 4.1) [25]. The trace wave length is the hypotenuse of the triangle formed by the line connecting the source (e.g. at the nozzle exit) with microphone and the axis of the microphone array, see Fig. 4.2. λs = f(λ,θ∗) = f(c, f,θ∗) = λ (4.1) cos(θ∗) Based on experience, aliasing effects tend to occur, when λs < 2∆xm. Analysis of various high frequency plots showed, that aliasing generally occurs starting with the 8000 Hz TOB. A verification simulation run, that is independent of the OPENAIR data, has been conducted using a constructed CSM that only contains one sound source at the nozzle outlet (x = 0) at 20 kHz. It uses a single steering vector gjm with the same microphone and source positions as the OPENAIR tests (see Eq. 2.13). The plot of the verification run can be seen in Fig. 4.3(a). There is a clear shape similitude in source directivity between the calculated and simulated CSM. The aliasing event SPL is approximately 40 dB below the main source.PDF Image | Investigation of wing installation effects on the sound field of a model jet engine
PDF Search Title:
Investigation of wing installation effects on the sound field of a model jet engineOriginal File Name Searched:
thesis-wing-install-effects-jet-engine.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |