THE OBJECTIVE OF THIS WORK IS TO STUDY HOW TO MINIMISE WAVE REFLECTION IN THE WAVE CHANNEL OF THE UNIVERSIDAD DEL BIOBIO WAVE LAB BY MEANS OF DIFFERENT POROUS MEDIA. THE EXPERIMENTAL STUDY WAS MADE DEFINING SIX INITIAL WAVE STATES, IN WHICH ALL EXPERIMENTS WERE CARRIED OUT. FOUR SITUATIONS WERE COMPARED: FIRST, WITHOUT ANY WAVE ABSORBER; SECOND WITH A SPONGE WAVE ABSORBER ALREADY PRESENT IN THE CHANNEL; THIRD WITH A POROUS PLATE ABSORBER IN SERIES; AND FINALLY WITH A TRIANGULAR MESH ABSORBER WITH SPONGES. WAVE TRAIN-FREE SURFACE ELEVATION DATA WERE COLLECTED USING THREE CAREFULLY SPACED ULTRASOUND SENSORS AND USED TO CALCULATE THE REFLECTION COEFFICIENT ASSOCIATED WITH EACH WAVE STRUCTURE AND PARAMETER. THE RESULTS REVEALED THAT THE FIRST SCENARIO SHOWED THE HIGHEST REFLECTION COEFFICIENT, WHILE THE SECOND SCENARIO SHOWED THE SECOND HIGHEST REFLECTION COEFFICIENT. ON THE OTHER HAND, THE THIRD SITUATION PRESENTED THE LOWEST REFLECTION COEFFICIENT, AND IN THE LAST SITUATION, A SLIGHTLY HIGHER COEFFICIENT THAN THE THIRD CASE WAS OBTAINED. THESE RESULTS HIGHLIGHT THE EFFICIENCY OF THE TWO PROPOSED ABSORBER STRUCTURES AND THEIR PERFORMANCE IN REFLECTION REDUCTION. IN CONCLUSION, THE POROUS PLATE ABSORBER SHOWED HIGHER MITIGATION OF THE REFLECTION, FOLLOWED BY THE TRIANGULAR MESH ABSORBER AND SPONGES. THIS STUDY COULD CONTRIBUTE TO FUTURE RESEARCH CONDUCTED IN THE WAVE-GENERATING CHANNEL, PROVIDING VALUABLE INSIGHT FOR PRACTICAL APPLICATIONS IN THE FIELD OF COASTAL RESEARCH AND ENGINEERING.

IN ORDER TO DESIGN AND EVALUATE THE BEHAVIOUR OF A NUMERICALLY OPTIMISED WAVE ENERGY CONVERTER (WEC), A RECOMMENDED PROCEDURE IS TO INITIALLY STUDY SMALL SCALE MODELS IN CONTROLLED LABORATORY CONDITIONS AND THEN PROGRESS FURTHER UP UNTIL THE FULL-SCALE IS REACHED. AT ANY POINT, AN IMPORTANT STEP IS THE CORRECT SELECTION OF THE WAVE THEORY TO MODEL THE DYNAMICAL BEHAVIOUR OF THE WEC. MOST AUTHORS RECOMMEND THE SELECTION OF A WAVE THEORY BASED ON DIMENSIONAL PARAMETERS, WHICH USUALLY DOES NOT CONSIDER THE MODEL SCALE. IN THIS WORK, THE SCALE EFFECTS FOR A POINT ABSORBER ARE STUDIED BASED ON NUMERICAL SIMULATIONS FOR THREE DIFFERENT REGULAR WAVES CONDITIONS. FURTHERMORE, THREE DIFFERENT WAVE THEORIES ARE USED TO SIMULATE TWO SCALES 1:1 AND 1:50. THE WEC-WAVE INTERACTION IS MODELLED BY USING A NUMERICAL WAVE TANK IMPLEMENTED IN ANSYS-FLUENT WITH A FLOATING OBJECT REPRESENTING THE WEC. RESULTS SHOW THAT THE NORMALISED DIFFERENCE BETWEEN 1:1 AND 1:50 MODELS, KEEPING THE SAME WAVE THEORY FLUCTUATE BETWEEN 30% AND 58% OF THE WEC HEAVE MOTION AND THAT A WRONG SELECTION OF THE WAVE THEORY CAN LEAD TO DIFFERENCES UP TO 138% FOR THE SAME VARIABLE. IT IS ALSO FOUND THAT THE LIMITS FOR THE USE OF WAVE THEORIES DEPENDS ON THE PARTICULAR MODEL AND THAT THE RANGE OF APPLICABILITY OF DIFFERENT THEORIES CAN BE EXTENDED.