## 1 Introduction  
The subject matter of the article is related to obstacle lighting lamps working in air traffic safety systems. Nowadays, such lamps are a crucial part of the warning system for air traffic vehicles due to the expansion of the world's aerial navigation [1]. They are also subject to international standards and air traffic rules, as established by the International Civil Aviation Organization [2], which are applied worldwide by the National Civil Aviation of various countries. Particular technological parametersas colors, luminous intensity, patterns, and also the location of the warning lamp installation are defined by these standards. These kind of lamps are commonly attached to tall structures such as e.g., chimneys, towers, transmission lines, or wind power turbines to make them visible for air traffic vehicles, especially in the night. There exist lighting devices of various intensities on the market, whose application depends on the location and operating conditions, e.g., under high pollution or mist environment. Depending on the particular location, it may be a hot or cold climate; thus, there exists a need for the lamps to operate under different weather and environmental conditions.  
Nowadays, it is a frequent procedure in the industry to perform computer simulations for complex systems instead of building numerous physical models of a device, which leads to savings in time and money [3]. For example, the subject of optimizing the size and shape of heat sinks for various lighting devices is now widely researched, especially in the field of numerical modeling, e.g., [4]. Frequently discussed in the literature is the cooling of light-emitting diode (LED) lamps with the use of natural and forced convection, e.g., [5; 6; 7]. Current trends in heat sink optimization in various constellations are described in detail in [8]. There are also published works of numerical analysis of the LED modules [9], but in our case, the whole model of the lamp is crucial. In [10], the authors consider a comparable subject matter, and a similar heating curve for a street lamp has been obtained, but their numerical model does not refer to the transient state but only to the steady state. Often, the published papers concern only theoretical analyses, without referring to a physical model, e.g., [7; 11]. A lot of interesting information about the modeling and measuring of LED-based light sources can be found in [12].  
The main goal of the authors is to develop a device with the ability to work in extremely difficult weather conditions. For example, the lamps currently being produced by BSSTC.PL Sp. z o.o. and OLATECH DR INZ. Andrzej Blachowicz are sold on the European market, but it is planned to develop a device that is able to operate in desert and equatorial conditions. An appropriate device, which is continuously illuminated, prior to its application in the industry needs to satisfy requirements according to national/international standards. Therefore, a computer model that enabled conducting research aimed at determining the optimal parameters of the lamp operation was developed. In particular, a simplified numerical model of the device was built using COMSOL Multiphysics and its Heat Transfer module, which applies the finite element method (FEM) for the calculation of integrated physics of heat propagation and airflow under the laminar regime. The model was validated using experimental data in a steady state. In subsequent sections, the numerical model, the measurement, and theoretical investigations results are presented.