Mieczysław Czechowicz, M.Sc., Eng.


Recent publications
1.Walerian E., Janczur R., Czechowicz M., The role of mutual screening by vehicle bodies in traffic noise propagation throughout a built-up area, APPLIED ACOUSTICS, ISSN: 0003-682X, DOI: 10.1016/j.apacoust.2013.07.014, Vol.76, pp.291-299, 2014
Abstract:

The paper presents the results of investigation of the sound field on a building façade neighbouring a busy road. The field simulation is based on programs which allow control of accuracy in description of a propagation process, as well as accuracy in modelling of a road and its surroundings. Considered interactions are straight-line spreading, reflections, and diffractions. The urban system modelling involves geometry of surrounding buildings and acoustical properties of their walls, road geometry and a traffic structure in lanes. By comparison of the simulation with the field measurements it could be confirmed that a proper accuracy has been obtained. Based on the verified simulation of the sound field, the efficiency of noise abatement means can be predicted depending on urban system parameters.

In the previous investigation, moving vehicles were modelled as omnidirectional point sources (E. Walerian, R. Janczur, M. Czechowicz, J. Smirnowa, Possible improvement of acoustical climate. PART I: Measurements and theoretical description, Archives of Acoustics 35 (3) (2010) 307–332; R. Janczur, E. Walerian, M. Meissner, M. Czechowicz, Application of simulation program to specific urban situation, Applied Acoustics 70 (2009) 973–985). In this way, the required agreement between the simulation and measurement had been obtained for the upper part of façades.

In the presented paper the free emission in the road space is replaced by emission disturbed by other vehicles’ presence. To consider their influence, the effect of mutual screening by vehicle bodies is included. The disturbed noise emission, when neighbouring vehicles are treated as semitransparent screens, offers a fully satisfactory agreement with field measurements for the case of a smooth façade. A noticeable improvement has been obtained for a shaped façade with a few meters depression in it. In the last case, the satisfactory agreement with field measurements has been reached when the proper reflection coefficient of the walls has also been assumed.

Keywords:

Screening by vehicle bodies, Vehicle modelling

Affiliations:
Walerian E.-IPPT PAN
Janczur R.-IPPT PAN
Czechowicz M.-IPPT PAN
2.Walerian E., Janczur R., Czechowicz M., Efficiency of screen application in built-up area, APPLIED ACOUSTICS, ISSN: 0003-682X, Vol.72, pp.511-521, 2011
3.Walerian E., Janczur R., Czechowicz M., Smyrnova Y., Validation of a complex urban noise model close to a road, APPLIED ACOUSTICS, ISSN: 0003-682X, DOI: 10.1016/j.apacoust.2011.04.009, Vol.72, pp.790-802, 2011
Abstract:

The adequacy of a model for the sound level close to a road is investigated by comparing resulting predictions for the sound level over a building façade with measurements. The road model involves the road geometry (the number and positions of traffic lanes), the traffic structure (vehicle flow rates and their average speeds in each lane) and equivalent omnidirectional point sources representing the vehicles. It is found that the assumed road traffic noise source model is adequate only for predicting levels over the higher part of the façade. However the investigation has allowed definition of what improvements are needed in the road source modelling to enable adequate predictions over the whole of the building façade.

Keywords:

Acoustical climate prediction, Noise sources modelling

Affiliations:
Walerian E.-IPPT PAN
Janczur R.-IPPT PAN
Czechowicz M.-IPPT PAN
Smyrnova Y.-IPPT PAN
4.Janczur R., Walerian E., Czechowicz M., Facade shaping as local means protecting against traffic noise, ACTA ACUSTICA UNITED WITH ACUSTICA, ISSN: 1610-1928, Vol.97, pp.769-778, 2011
5.Walerian E., Janczur R., Czechowicz M., Smyrnova Y., Possible improvement of acoustic climate. Part I: Measurements and theoretical description, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.35, No.3, pp.307-332, 2010
6.Walerian E., Janczur R., Czechowicz M., Smyrnova Y., Possible improvement of acoustic climate. Part II: Possible solutions, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.35, No.4, pp.595-618, 2010
7.Janczur R., Walerian E.M., Czechowicz M., Road model as a noise source, ACTA ACUSTICA UNITED WITH ACUSTICA, ISSN: 1610-1928, Vol.95, No.1, pp.156-167, 2009
8.Janczur R., Walerian E.M., Meissner M., Czechowicz M., Application of simulation program to specific urban situation, APPLIED ACOUSTICS, ISSN: 0003-682X, DOI: 10.1016/j.apacoust.2008.11.002, Vol.70, No.7, pp.973-985, 2009
Abstract:

In the paper, the simulation program predicting the sound level has been applied to one of buildings neighbouring a road. In the simulation are considered: geometry of road surroundings, the shape of the investigated building façade including, road geometry (number of lanes and their positions) and traffic structure (vehicle flow rates and their average speeds). Adjustable accuracy in an urban system modelling allows finding the model which is adequate to the real system. For the model of the accuracy limited by the simulation error due to vehicle speed estimation, by comparison with the field measurement, the model validation range has been established. Based on the simulation adjustable accuracy, possibilities of the validation range extension have been analysed.

Keywords:

simulation, traffic noise, noise protecting means

Affiliations:
Janczur R.-IPPT PAN
Walerian E.M.-IPPT PAN
Meissner M.-IPPT PAN
Czechowicz M.-IPPT PAN
9.Janczur R., Walerian E.M., Czechowicz M., Influence of vehicle noise emission directivity on sound level distribution in a canyon street. Part I: Simulation program test, APPLIED ACOUSTICS, ISSN: 0003-682X, Vol.67, pp.643-658, 2006
10.Janczur R., Walerian E.M., Meissner M., Czechowicz M., Influence of vehicle noise emission directivity on sound level distribution in a canyon street. Part II: Experimental verification, APPLIED ACOUSTICS, ISSN: 0003-682X, DOI: 10.1016/j.apacoust.2005.12.003, Vol.67, pp.659-679, 2006
Abstract:

In the paper, predictions of relative sound level distribution on building facades in city-centres obtained by using the simulation PROP11 program are compared with measurements. The simulation involves the geometry of surrounding buildings, road geometry (number of lanes and their positions) and traffic structure (vehicle flow rates and their average speeds). The agreement between measurement and simulation results is tested for different directivity characteristics of an equivalent point source representing the vehicles.

Keywords:

predicted sound level in built-up area, vehicle noise emission directivity

Affiliations:
Janczur R.-IPPT PAN
Walerian E.M.-IPPT PAN
Meissner M.-IPPT PAN
Czechowicz M.-IPPT PAN
11.Walerian E.M., Janczur R., Czechowicz M., Noise level spread in the vicinity of crossroads, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.30, No.1, pp.19-56, 2005
Abstract:

In the paper, the PROP10 program is used to present the time-average sound level on façades of buildings in the vicinity of a crossroads. The propagation model within an urban system forming canyon streets includes the wave interaction with obstacles, multi-reflections from building walls and single and double diffraction at their wedges. For the current purpose the program is provided with a road model in which the vehicle route is divided into sub-segments with lengths and linear densities of emitted energy that depend on the traffic organization in the vicinity of the crossroads. The lengths of the sub-segments, where vehicles wait and are forced to a subsequent start and stop, depend on the flow rates on lanes, the equivalent vehicle length, the red and green light times and the speed of leaving a crossroads. The linear energy density at these sub-segments depends on a parameter characterizing the energy emitted during the starting of a vehicle. The time-average sound level is analyzed as a function of the enumerated parameters.

Keywords:

traffic noise, interrupted movement, canyon street

Affiliations:
Walerian E.M.-IPPT PAN
Janczur R.-IPPT PAN
Czechowicz M.-IPPT PAN
12.Meissner M., Czechowicz M., Experimental investigation of flow-induced acoustic oscillations in piping system with closed branches, APPLIED ACOUSTICS, ISSN: 0003-682X, Vol.45, No.4, pp.359-375, 1995
Abstract:

An experimental study of flow-excited acoustic oscillations in piping systems with closed branches is presented in this paper. An influence of acoustic interactions between branches on a generated sound was investigated in arrangements with two and three branches. Significant changes of frequency and level of oscillation in terms of branch lengths were observed. In the system with three branches, at the specified lengths of one branch, a cancellation of oscillations was noticed.

Keywords:

piping system, closed side branches, flow-induced oscillations

Affiliations:
Meissner M.-IPPT PAN
Czechowicz M.-IPPT PAN

List of chapters in recent monographs
1.
191
Walerian E.M., Janczur R., Czechowicz M., Renewable energy: innovative technologies and new ideas, rozdział: Acoustical screens as local noise protector, Warsaw University of Technology (Warsaw), Chwieduk D., Domański R., Jaworski M. (Eds.), pp.397-404, 2008