Application of holography in jet acoustic studies

On nearfield acoustic holography

Such functions u are called radiating solutions. Pressure measurements are taken by acoustical sensors located in a domain Ω0 inside or outside the cabin or on a surface Γ0 = ∂Ω0 . Our goal is to reconstruct u inside Ω, or the normal velocity v = ∂νu on Γ = ∂Ω, (ν is the unit exterior normal to ∂Ω). This is a mathematical model of the nearfield acoustic holography [W], [Wu]. H(m)(Ω) denotes the...

Characterization of rocket and jet noise using near-field acoustic holography methods

As rockets and jets on military aircraft become more powerful, the noise they produce can lead to structural fatigue, hearing damage, and community disturbances. Noise-reduction technologies and sound radiation prediction require accurate characterization of the noise sources within rocket plumes and jets. Near-field acoustical holography techniques were used to visualize the sound field in the...

application of brand personality scale in automobile industry: the study of samand’s brand personality dimensions

این تحقیق شخصیت برند سمند را در ایران با استفاده از مدل پنج بعدی آکر (1997) بعنوان یک چهارچوب بطور توصیفی سنجیده است. بنابر این چهارچوب که دراصل در 42 جزء (42 ویزگی شخصیتی) ودر پنج بعد شخصیتی طراحی شده بود ودر کشورها وصنایع مختلف آزموده شده بود, پرسنامه به زبان فارسی ترجمه شده و با استفاده از روشهای ترجمه معکوس و مصاحبه عمیق با 12 متخصص ایرانی به 38 جزء کاهش یافت. و نظرسنجی ای در پنج نمایندگی ا...

Application of Near-field Acoustic Holography in Presence of High Temperature Gradient: Experimental Uncertainty Analysis

Near-field Acoustic Holography (NAH) has been shown to be a powerful tool for the study of sound radiation from vibrating structures. It provides the reconstruction of acoustic pressure, intensity and particle velocity in the space starting from pressure measurements made on a plane array near the vibrating structure. The reconstruction of the sound field is based on measurement of cross-spectr...

Experimental Studies of Inverted - Profile Coaxial Jet Flows