SIDLAB 4.1.0 Release Highlights
- Simulation of multi-inlet and multi-outlet systems is now possible. It is possible to define more than one inlet and more than one outlet for the system.
- New CAD viewer inside SIDLAB to visualize the muffler models. Supported formats are .stl, .obj, .x3d, .fxml, .col and .3ds.
- Possibility to stop the calculation at any time using Ctrl+C.
- Pan and automatically extend the network.
- More realistic network drawing with new icons and special connection direction for some elements such as Bends and End caps, which are connected in 90 degrees.
- Updated SIDLAB-MATLAB connection.
- Support user-defined files with unequal frequency vector.
- Compare Insertion Loss with reference system and calculate the difference.
- Fixed a bug with exporting and comparing octave band plots.
- Handle medium resolutions in most recent generation of laptops.
- Handled an interface problem that caused by some new high resolution display cards.
- When user chooses inches: Flow is considered in lb/s, ft/s and ft/min, Temperature in F, density of absorbing material lb/ft3.
- Easier order calculations vs. RPM.
- You can do simple calculations inside the text fields.
- You can define variables with values inside projects and use them in defining your data.
Low frequency Acoustics Calculations
- Calculate the Flow Generated Noise for some elements (straight pipes – orifice – perforate – bend – open end – multi-port perforated elements).
- “Two Mic” is a new element to calculate the Reflection Coefficient and Impedance as seen from the pipe. This is similar to a two-microphone measurement.
- New element to calculate the transfer matrix from Finite Element Calculation. This requires two different solutions for the same system with two different boundary conditions by an external FEM Software; e.g. COMSOL Multiphysics.
- New technique to calculate Insertion Loss based on radiated sound pressure from the system outlet.
- The bend element now considers the length of the bend.
- A Transparent element is now transparent in flow calculation as well as the acoustic calculation.
- Improvements and bug fixes in the optimization module.
- Simulation of flow circulation using bends without affecting the acoustics results.
- Simulation of Baffle Silencers are now available in below the plane wave range.
- Optimization of specific paths for networks with multi inlets and outlets.
Acquisition and Measurement
- Automatic detection of connected acquisition cards.
- Measurement of the background noise inside the rig.
- Measurement of the coherence between the microphones.
- Estimate the time needed for the measurement and display the actual elapsed time during the measurement.
- Measurement of temperature, flow velocity, and pressure drop is now available. All data are acquired automatically and processed for accurate results.
- Automatic control of the fan speed from SIDLAB software.
- Smooth switching between different frequencies during stepped sine measurements to decrease the measurement time.
- Save several versions within the same project file.
- Save different plots inside the project file.
- Compare with selected versions inside other SIDLAB files.
- Plot of acoustic pressure, coherence and transfer functions immediately after the measurement ends (before calculations).
- Calculate and plot the flow-pressure drop curve.
- In active one-port measurement, it is now possible to handle different types of tachometer signals, square pules or spike pulse.
- SIDLAB Measurement and SIDLAB Acquisition are combined to the same interface.
- Measurement of higher frequencies beyond the plane wave limit is now possible using a new Test Rig configuration.
- Acquisition and Measurement modules are now united in one module.
- Measure the Flow generated noise from the measured object.
Installation and Licensing
- License activation is now faster and easier than before.
- More friendly handling of license error issues.
- License borrowing for Floating Network License is now available.
- There is no need to install JAVA runtime engine.
- Update to latest version of MATLAB compilers.
- SIDLAB and SIDLAB Installer are now signed with a certificate.
High frequency Acoustics Calculations
This new module models the propagation of sound inside ducts in the high frequency range using power method. It is hard to specify accurately at which frequency this range starts but it is assumed that high frequency region begins from double to three times of cut-off frequency of the first mode, in this range a large number of modes are exists and wave length is very small so that sound is propagate as rays and there is no coupling between a source and a system and the acoustic power equals the free field value. In this range, the power based methods can be used, this implies that each source is described by its power and each duct element by its transmission coefficient.
The standard procedure is to use power based calculation models. These models are often based on measurements. All sources are associated with a sound power based on a standardized measurement. This sound power is then assumed to propagate through a pipe system and to behave like a semi-diffuse field, and as traditional assumption in HVAC calculation the effect of reflections at junctions, bends and cross section sudden change are neglected. This model is similar to the classical power based models used for room acoustics.
In power based techniques, the source-path-receiver model is used, see Figure 1. In this model, the source is the sound-generating device; the path comprises everything that affects the sound as it travels from the source to the receiver, and the receiver is typically the site where a person hears that sound. The term element collectively describes the source, receiver, and path components. The receiver location hears the sum of all sound traveling to that location. Depending on the application, there may be several sources of sound, and the sound from each source may travel to the receiver along one or more paths. Regardless of the number of sound sources and paths, each path is analyzed individually; then the superposition of all paths is considered. This model is widely used in HVAC applications.
The path is analyzed by adding and subtracting the regenerated and attenuated power to this path sum at each Octave or Third Octave frequency band. It is usually assumed that reflections are minor and therefore their effect is neglected. Moreover, elements that produce backward reflections, are considered as attenuation without affecting the elements connected to it.
SIDLAB Acoustics HF calculates:
- Insertion Loss in Octave bands (dB and dBA), for any combination of inlet/outlet of the system.
- Pressure outside the network, either radiated in free field or inside Rooms.
Standard Two-port elements in high frequency
- Diffuser Rectangular
- Lined duct
- Lined duct Rectangular
- Lined flexible duct
- Area Expansion
- Area Contraction
- Expansion Chamber
- Bend Rectangular
- Damper Rectangular
- User defined attenuation
- Baffle Silencer
Standard One-port elements in high frequency
- Open end
- Terminal Diffuser
- Terminal Diffuser Rectangular
- User Defined Inlet
Standard Branching nodes in high frequency
- Cross Rectangular
- T Junction
- T Junction Rectangular
- T Side Branch
- T Side Branch Rectangular
Standard Sources in high frequency
- Fan Sound Power
- User Defined Inlet Sound Power
Example of HVAC system simulation
Current list of Tutorials for all SIDLAB Modules:
- Simple Expansion chamber
- Reactive muffler
- Through flow muffler
- Through flow muffler with absorbing material
- Muffler with perforated baffle filled with absorption
- Single plug muffler
- Double plug muffler
- Eccentric muffler
- Engine order
- Engine source
- User defined elements
- After treatment device
- Lawn Mower Muffler
- Two-inlet single outlet muffler
- User Defined FEM Project
- Multi perforate muffler.
- Two mics Project
- Reflection free termination.
- Closed pipe termination.
- Open end termination.
- Muffler Optimization Example 1
- Muffler Optimization Example 2
- Engine Source TL Optimization (This is named with “Muffler Optimization Example 2”)
- Engine Source TL Parameterization (This is named “Parametrization”)
- HVAC system
- High frequency muffler
Acquisition / Measurement modules
- Active one-port measurement
- Passive two-port measurement
- Stepped Sine acquisition
- White Noise acquisition