This simulator places a porous fibrous specimen on a rigid backing and sends a normal-incidence wave into it. Set the absorption coefficient, incident pressure, specimen area and frequency, and watch incident power divide into a reflected part and an absorbed part while accumulated absorbed energy grows.
• A 3D view with an incident wave launcher, a porous fibrous specimen, the rigid backing behind it, the reflected wave path and dissipation markers. • Sliders for the specified absorption coefficient, incident RMS pressure, specimen area and excitation frequency. • Six readouts: incident power, reflected power, absorbed power, pressure reflection magnitude, accumulated absorbed energy and a power-balance error. • Curves & measurements with equations, two guided presets with a verification bench, and Learn & assess lessons and quiz.
Incident power is Pin = p²rms A / (ρc). A fraction α, the absorption coefficient, is absorbed and the remainder 1 − α returns, so Pabs = α Pin and Pref = (1 − α) Pin. Pressure amplitude uses a different ratio: |R| = √(1 − α). With α = 0.75 the reflected pressure is half the incident pressure, yet only a quarter of the power comes back.
Absorbed energy accumulates as Eabs = Pabs t, and the power-balance readout confirms that absorbed plus reflected equals incident.
The absorption coefficient is specified at the selected frequency; the model does not predict it from material thickness or flow resistivity, and real absorbers change strongly with frequency. There is no transmission through the backing, no temperature rise, and absorbed energy uses physical time equal to animation time divided by 100. Treat it as a clear demonstration of power accounting, not a material selection tool.
Seventy-five percent of the incident acoustic power is absorbed and converted to heat inside the material, and 25 percent is reflected. The reflected pressure amplitude is then √0.25 = 0.5 of the incident amplitude.
Power is proportional to the square of pressure. The reflected power fraction is 1 − α, so the pressure reflection magnitude is the square root of that value.
With α = 0 the absorbed power is zero and all incident power returns, which is the first guided experiment. The accumulated absorbed energy stays at zero.
No. The absorption coefficient is an input at one frequency. The model has no thickness, density or flow-resistivity prediction, so it teaches the power balance rather than selecting products.