課程簡介

ACTRAN 是著名的聲學軟件提供商--比利時FFT公司的旗艦產品。本課程由海基科技副總李奇博士講授，李奇博士畢業于同濟大學聲學所、瑞典皇家工學院航空與車輛工程系MWL實驗室，具有十年以上聲學仿真經驗，是資深CAE專家。本課程為ACTRAN Acoustic workshop基礎課程，為您詳細、全面介紹ACTRAN Acoustic workshop。

?

課程目錄

1 1A Description of Actran workshop

• ?

  1 To import an ACTRAN input file and check the content of it

  2 To export both the mesh and the input file

  3 To launch in different ways the input file

2 1B-1 Example of sound source in a treated cavity(foam layer)

• ?

  1 One considers the same cavity as in workshop 1A but one layer of fluid elements is replaced by a foam layer

  2 Sound in enclosure: a spherical source is placed in one corner of a 1m3 cavity wuth 5 rigid walls and a foam layer

  3 A 0.125m thick foam layer is glued against one of the cavity walls(from y=0.375m to y=0.5m)

  4 Use rigid porous elements

3 1B-2 Training of Kundt's tube

• ?

  1 Problem description and models

  2 Workshop description

  3 Using BOXPRO as a pre-processing tool

4 1C Using equivalent admittance

• ?

  1 One considers the same cavity as in previous workshop

  2 The spherical source placed in one of the box corner at (x,y,z)=(-0.375,-0.375,-0.375)

  3 Use an admittance boundary condition for modeling the foam

  4 Computed results(compare with workshop 1A)

  4.1 The mean square pressure amplitude from 1Hz to 500Hz

  4.2 The sound pressure level at the center of the box

  4.3 Plot a color map at 295Hz

5 2 Model extraction: acoustic cavity

• ?

  1 One considers a 1m3 cavity, centered on the origin(0,0,0)

  2 One considers default air properties for the fluid and assumes the walls to be rigid

  3 Use quadratic, 0.125m sized elements

  4 Post- processing:

  4.1 Extract the modes in the 1Hz to 500Hz frequency range

  4.2 Plot a color map of 7th mode(order(m,n,l)=(1,1,1)) and compare it with the workshop 1A map

6 3 Free field radiation of a monopole

• ?

  1 Purpose: free-field radiation of a monopole in air at standard conditions

  2 Plot the real part of the pressure from 1Hz to 500Hz measured at (x,y,z)=(1,0,0)

  3 Plot the sound pressure level from 1Hz to 500Hz measured at (x,y,z)=(1,0,0)

  4 Visualize a map using cutplanes functions

7 4 Duct radiating in free field

• ?

  1 One considers a simple duct radiating in a half free space

  2 The duct is excited with each mode propagating at 700Hz

  3 Compute the pressure variation along the duct axis

  4 Plot a color map

8 5A BC_MESH application: structure radiating in a free field

• ?

  1 The objective of this workshop is to evaluate the acoustic radiation of a simple vibrating structure

  2 The parameters of the problem

  3 The displacement of the edges of the panel are set to 0

  4 The excitation is displacement at the center of the plate

9 5B Training

• ?

  1 The objective of this document is to explain how to create an ACTRAN model in order to compute the acoustic radiation of a vibrating structure

  2 This training is based on a gearbox model

10 6 Visco-thermal effects in Actran

• ?

  1 Visco-thermal elements in Actran

  2 Purpose: understand the visco-thermal effects occurring in a thin circular tube connecting to acoustic cavities

  3 Plot the SPL of the pressure from 10Hz to 3000Hz measured at (x,y,z)=(0.05,0.6,0) for 2 cases: with and without visco-thermal effects in the thin tube

  4 Plot the average SPL in the different cavities

  5 Visualize pressure maps at some frequencies of interest