This report investigates the aero-acoustic noise generated by sheet metals of three different structures. The investigation is done both experimentally and numerically in order to find the sheet of best acoustic performance. Each sheet was tested experimentally in a wind tunnel in the velocity range of 9 to 20 m/s where the produced sound was recorded by a microphone. The experiment aimed at finding which sheet produces louder noise. Moreover, the velocity fluctuation after the sheets trailing edge was captured by a Hot Wire Anemometer to find the dominant frequency of vortices and calculate turbulence intensity. Finally, the case of highest velocity was numerically simulated using Ansys fluent where the simulation was validated by the experimental results. The numerical analysis used LES turbulence model with Kinetic Energy Transport sub-grid model. Ffowcs-Williams & Hawkings model was used to predict the acoustic sources. Agreements were found between the trend of acoustic noise produced from experiment and numerical simulation over some ranges of frequency.
Anotace v angličtině
This report investigates the aero-acoustic noise generated by sheet metals of three different structures. The investigation is done both experimentally and numerically in order to find the sheet of best acoustic performance. Each sheet was tested experimentally in a wind tunnel in the velocity range of 9 to 20 m/s where the produced sound was recorded by a microphone. The experiment aimed at finding which sheet produces louder noise. Moreover, the velocity fluctuation after the sheets trailing edge was captured by a Hot Wire Anemometer to find the dominant frequency of vortices and calculate turbulence intensity. Finally, the case of highest velocity was numerically simulated using Ansys fluent where the simulation was validated by the experimental results. The numerical analysis used LES turbulence model with Kinetic Energy Transport sub-grid model. Ffowcs-Williams & Hawkings model was used to predict the acoustic sources. Agreements were found between the trend of acoustic noise produced from experiment and numerical simulation over some ranges of frequency.
This report investigates the aero-acoustic noise generated by sheet metals of three different structures. The investigation is done both experimentally and numerically in order to find the sheet of best acoustic performance. Each sheet was tested experimentally in a wind tunnel in the velocity range of 9 to 20 m/s where the produced sound was recorded by a microphone. The experiment aimed at finding which sheet produces louder noise. Moreover, the velocity fluctuation after the sheets trailing edge was captured by a Hot Wire Anemometer to find the dominant frequency of vortices and calculate turbulence intensity. Finally, the case of highest velocity was numerically simulated using Ansys fluent where the simulation was validated by the experimental results. The numerical analysis used LES turbulence model with Kinetic Energy Transport sub-grid model. Ffowcs-Williams & Hawkings model was used to predict the acoustic sources. Agreements were found between the trend of acoustic noise produced from experiment and numerical simulation over some ranges of frequency.
Anotace v angličtině
This report investigates the aero-acoustic noise generated by sheet metals of three different structures. The investigation is done both experimentally and numerically in order to find the sheet of best acoustic performance. Each sheet was tested experimentally in a wind tunnel in the velocity range of 9 to 20 m/s where the produced sound was recorded by a microphone. The experiment aimed at finding which sheet produces louder noise. Moreover, the velocity fluctuation after the sheets trailing edge was captured by a Hot Wire Anemometer to find the dominant frequency of vortices and calculate turbulence intensity. Finally, the case of highest velocity was numerically simulated using Ansys fluent where the simulation was validated by the experimental results. The numerical analysis used LES turbulence model with Kinetic Energy Transport sub-grid model. Ffowcs-Williams & Hawkings model was used to predict the acoustic sources. Agreements were found between the trend of acoustic noise produced from experiment and numerical simulation over some ranges of frequency.
The structured metal sheets are commonly used in many applications and recently can be found in many parts of the car starting from the car bodywork up to the engine space. Just in this last mentioned application the metal sheets protect the car inside environment against noise and heat load. The objective of the work will be a study of the structures on the noise and heat damping in relation to the car interior. The verification of the numerical and experimental approaches will be studied as well. This work will be carry out in a collaboration with a German university. The condition of the work is a short-term stay at the university in Germany. The assumed result: a selection of the appropriate structure in respect of the main protection function of the metal sheets.
Zásady pro vypracování
The structured metal sheets are commonly used in many applications and recently can be found in many parts of the car starting from the car bodywork up to the engine space. Just in this last mentioned application the metal sheets protect the car inside environment against noise and heat load. The objective of the work will be a study of the structures on the noise and heat damping in relation to the car interior. The verification of the numerical and experimental approaches will be studied as well. This work will be carry out in a collaboration with a German university. The condition of the work is a short-term stay at the university in Germany. The assumed result: a selection of the appropriate structure in respect of the main protection function of the metal sheets.
Seznam doporučené literatury
\matsymb{lbrack}1\matsymb{rbrack} R.L.Webb, N.Kim, Principles of Enhanced Heat transfer.Taylor-Francis, 2005, ISBN 1-59169-014-5.
Seznam doporučené literatury
\matsymb{lbrack}1\matsymb{rbrack} R.L.Webb, N.Kim, Principles of Enhanced Heat transfer.Taylor-Francis, 2005, ISBN 1-59169-014-5.
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